In some cases, big-pharma companies make their own generic drugs to prevent competition. I don’t see why food producers would’t do the same.
They have to deliver them anyway, and they want the shelves to be stocked in a way that shows their goods bet.
Not *all *of them; the vast majority of product came from a regional warehouse that supplied national brand products to every supermarket in the area, and the store’s own employees restocked them.
However, a few large companies with their own local distributors, e.g. Frito-Lay/Pepsi, Coke, certain brands of bread, bottled water, a few random dairy products, and some other random items had their own reps deliver and restock the shelves themselves.
Store brand is okay for many things (Safeway used to have the best salsa), but I’ve seen the expansion of store brands too. For example, I prefer Veg-all Mixed Vegetables. In 3 out of the 4 groceries I shop at, they have store brand mixed veg (mushy, tasteless, mixed veg w/o limas) and no Veg-all. Only one carries Veg-All brand (plus the exceptionally fine No-sodium added variety). I really hate to drive to that one grocery just because I like one product, but I do.
Here in the Eastern states of Australia where Aldi and Costco are becoming bigger and stronger by the minute our major chains, Woolworths and Coles are mimicking both more and more. A lot more store brands at various quality and price points as Aldi’s growing market share with mostly their own labels has shown we don’t have the brand loyalty they previously assumed, as well as many more buy 2 for $20 or 1 for $15 type deals and specials on huge bulk packs they didn’t even carry before.
They even do that at Walmart (at least some walmarts) - Chips,Soda, Bread, Some dairy stuff (and stuff also sold by the dairy), and cookies/crackers/snack cake type items, of certain brands. In particular Coke/Pepsi, Oreos, Wonder bread, Twinkies (at least pre-bankruptcy), etc.
You might remember this Pepsi commercial from the 1990s, which shows a Coke delivery guy who surreptitiously drinks a Pepsi.
Frozen foods of course is the area where space is at a premium. The refrigeration costs per foot of display space are huge. The retailer has to trade-off more varieties for more brands. Customers are not really willing to pay much of a premium for Birdseye, certainly not enough to keep the “penny profit” equal to that of the store brand. So the retailer can carry 40 varieties of one brand or 20 varieties of two brands each. A workable compromise is to carry 30 varieties of store brand and 10 brands of Birdseye or Green Giant.
A more realistic cost/retail relationship might be cost of $1 for the store brand and retail of $1.99. The cost on Birdseye might be $1.40. There are some customers who might shell out $2.39 for Birdseye, but if the retailer didn’t carry the $1.99 store brand they would lose customers to competitors who did.
Frozen dinners and ice cream are a different matter. The brands are a lot more powerful in terms of customer loyalty.
Here in the Midwest I have noticed this myself. I’m familiar with co-packing (a company which makes a labeled brand also canning or bottling a product under a different label for a different customer) so I always watch the shelves when I go to the store. There are only three grocery store chains in my town ( Wal*Mart, Meijer and Kroger) and all three have increased their shelf space for their own branded items and have placed some premium items on higher shelves or dropped them entirely.
I was thinking that the reason for this may be that some food suppliers might be balking at paying the chains the “perks” that they do to get their product in the the best location. This might due to the increases in food costs overall leaving the manufacturers and the distributors less profit to play with and thus less to give to the store chains.
I have also noticed that in my area both Kellogg’s and General Mills have been paying for more end caps and aisle displays. They are apparently trying to keep their sales up.
What you get with national brands is consistency - every can of DelMonte Sliced Pears will have the same texture, firmness, and taste as every other.
Just as people will travel across the country and still eat McDonalds.
Store brands can vary - some products are indistinguishable from the national brands, some are decidedly different.
If you go to the same store every time, try picking up a house brand and compare - if it is the same, save yourselves a buck.
The two major supermarket retailers in Australia (Woolworths and Coles) are not ‘dumping’ the brand name products, but are placing their homebrands strategically upon the shelves. Once upon a time the higher-priced goods were where the home-brands are now, but they are now in less accessible shelves.
So the consumer sees the home-brand stuff…looks around to see what else is on offer, and finds the cheaper stuff right where they looked in the first place!
However, the home-brand products are more likely made from imported goods thus ensuring that they remain competitive with the locally made stuff.
In the end, the supermarket wins, and the local growers lose out big time. 
I’m finding that supermarkets are discontinuing their own-brand alternatives for some things - you were going to buy a jar of apricot jam anyway - now you have to buy the more expensive one.
Ever been to a military commissary? Its almost always super generic meaning you buy a can that says “Coffee” or “Coffee - decaffeinated”.
As economic indicators go, this is probably quite a good one. In 2008 I was working in retail analysis and it was striking just how widely supermarket branded goods were able to spread. They soon became the number one or two brand in a wide variety of markets as people tuned into the signal that they represented value for money. Even Waitrose has its wonderfully named Essentials range (Essentials including pancetta, creme fraiche, smoked salmon, for example). Whether or not these private-label goods were actually cheaper, they certainly sold on the basis of value for money for the canny shopper.
If supermarkets are now pushing brands again, it’s seems like a pretty clear indication that they think we not only can spend the money, but want to.
In my experience, yes, the supermarkets are not carrying as many name brands. For example, I like Brach’s jelly beans. I used to run to the store every once in a while and get a bag. About six or seven years ago I realized I couldn’t find them at the grocery stores, but I could at the drug store. The grocery stores had started stocking their own brands.
Then about five years ago the drug store quit carrying them, and started carrying their own brand instead, but most of the stores would stock them at Easter, so I would buy a couple of bags.
This month I went to get some jelly beans, but even though it’s Easter, all I see are store brands. I finally found some Brach’s at Walgreen’s for $4.99 a bag, next to Walgreen’s brand which was selling for less than half that.
I also see it in the cookie aisle and canned vegetable aisle.
Maybe I should eat more healthily.
To offer more specific reasons here, HEB (really, it’s in Texas, not the southwest in general) is a pretty big exception to the information in the other posts.
HEB has almost always sold products under its own brands once it got big enough. And, unlike the cases mentioned above, the HEB branded products are predominantly manufactured by HEB itself, mostly in Texas. For example, they produce the 2nd most bread and ice cream in the state under their brands. In this case, it’s not the same production facilities as the big name brands but entirely different facilities. And since it’s all going to HEB (and Central Market) stores to be sold, advertising can be folded into advertising for the chain itself rather than specifically for the products.
ETA: note that the “local” touch is important to Texans. The biggest bread and ice cream brands in Texas by volume sold are Mrs Bairds and Blue Bell, which are also marketed heavily locally to Texas. That HEB offers low priced local goods does go a long way.
To some extent, that’s to combat Kroger and Wal-Mart as purveyors of lower priced goods manufactured in Texas for Texans, but it’s also just the way they’ve always done things.
There was a time when “store brand” = “second rate”, but not any more. I’ve noticed this as well, especially here in San Antonio where most people shop at HEB.
ETA: Just read that you, too, shop at HEB. So maybe it’s a chain thing?
Maybe HEB is taking private-label to the next level. I’m used to the private-label brands being a more basic, 2nd tier product. But HEB is trying to make it the premium choice. For example, their private-label tortillas come in many more variations than the regular brands ever did. And now that the regular brands are relegated to the edges of the section, they have even less variety now than they did before. The regular brands are becoming the more basic choice.
Trader Joe’s can’t be compared to traditional grocery stores, because their entire selection is based on their store brand. They do carry name-brand products, but they seem to be more about filling in the gaps because Trader Joe’s can’t feasibly produce a store brand for every single thing they want to carry.
Costco has largely succeeded in doing that with their Kirkland brand, at least for many products. For example, Kirkland tuna fish is far superior to the regular supermarket brands and it’s about the same price.
Pathmark (owned by A&P) has done something interesting by producing a second-tier store brand that is cheaper than its regular store brand. The few products that I’ve tried from that line have been far inferior to the regular store brand items. It was an unpleasant surprise because I’d gotten used to the idea that store brands are usually in the same quality range as typical name brands, at least in some categories.
But first check and make sure that you really are saving. Store brands are not always cheaper than the competition. It pays to do a price comparison, since some people will simply grab the store brand on the theory that it ought to be cheaper, without realizing that it’s not.
Yet another reason to spring for Amazon Prime. 
I have definitely noticed the disappearance of certain name brands from my Safeway. Now I do my grocery shopping at a whole series of stores in order to find the specific products like. I do like some Safeway brands (Lucerne dairy products are excellent), but others are not up to the standard of the name brand.