What recipes or food combos have gone from non-existant to ubiquitous in your lifetime? Buffalo wings would be the obvious example here in the States; ethnic foods that are simply gaining popularity (hummus, taco, etc.) where you are aren’t as notable.
Macadamia nut/white chocolate cookies, for example…never remember them as a kid.
The Asiago cheese craze of about 10 years ago was weird. It was a really niche cheese that nobody knew about. Then all the sudden it was everywhere. Asiago bagels, Asiago pizza crusts, commercials for Asiago crusted chicken at Applebee’s, shredded on salads.
Now it’s mostly not talked about anymore again.
Ranch dressing. Never heard of it when I was a kid, but by the 80s, it was all over and is now inexplicably the most popular salad dressing in the US.
Mixed drinks often follow this pattern. The Cosmopolitan, for instance, didn’t exist before the 80s, nor did many of the martini variations like the appletini. The tequilla sunrise came out of nowhere to be the big drink on campus in the early 70s (when college students could still drink legally) to where they don’t seem to exist any more.
My husband and I were just talking about that last night. I remember the very first time I tasted Ranch dressing in the late 80’s and had never heard of it before then, now it’s offered as a dip for french fries, along side the buffalo wings mentioned in the OP and even some pizza places offer it as a crust-dipping sauce. It seems it just appeared out of nowhere and took over. 
“California” foods came in in the 90’s - sundried tomatoes, artichoke hearts, and goat cheese were on everything. Which is awesome, because before then you couldn’t find them in South Carolina.
Later, chipotle.
Well, I’m aging myself here, but I can remember cautiously trying frozen yogurt for the first time. A few years later they seemed to be everywhere. Suddenly it seemed like every block had a frozen yogurt store, a video store, and a tanning salon.
Those blended iced coffee beverages showed up a few years later.
If I had to guess, I would say that there were probably only a handful of Thai restaurants in the entire country 20 or 30 years ago; now (even here in lilly-white Salt Lake City) they are on every other mollyfocking street corner…
(Which is actually not a bad thing, as I enjoy Thai food on occasion) 
Also, Salt Lake IS getting more diverse, but the vast majority of our minorities are from Mexico and Central America
The reason I mentioned ethnic foods in the OP as not being ideal examples was because they really didn’t come from “nowhere”…they did have Thai food in Thailand before the restaurants invaded, right?
Along the lines of ranch dressing - last week I ordered onion rings instead of fries at a bar/restaurant and it came with the same perfectly complementary sauce I thought originated at the Outback. If this ain’t everywhere yet I hope it will be - blows ketchup out o’ the condiment water.
I obviously didnt read your OP carefully enough—Sorry…
How about turkey as anything other than the massive, roasted Thanksgiving main course? I’m talkin’ ground turkey, turkey sausage, turkey cutlets, etc.
No apology necessary…I hope I didn’t come across as being snarky 
Glad to here SLC is moving in that direction… when the Cuban food shows up, you’ve arrived!
Beer. “Handcrafted” beers, brew-pubs, micro-brews and all that. Anything other than standard american light lager.
I suppose microbrew beers.
I never heard a single word about them as a kid (born 1981)
When I hit drinking age - in a beer drinking town - at the beer drinkingist University (Madison, WI) it was still pretty much just Bud, Miller or the Beast.
I remember it was kind of a neat novelty in about 2003 to visit a brewpub.
Of course, since then there are like infinity microbreweries. Hell, I can walk into my local liquor store and find at least 200 different brands. It’s gotten a bit silly.
Not in the least
I am racking my brain to find a good example, but all I am coming up with is the emergence of “gourmet” pizza toppings several years back.
Pine nuts, artichoke hearts, kalamata olives, albatross…
When I was a kid, it was still just the basics (pepperoni, mushrooms, sausage etc.) but even frozen pizzas are offering the gourmet toppings now.
Flavored colas, like cherry or vanilla or lime coke. When I was a kid you could get cherry Coke at soda fountains (and they had more cherry in them), but not ready-made.
The Blooming Onion.
Some of this could be personal awareness based on age. GameHat mentions that brewpubs hit in 2003… when he was 22. Well, I was born 20 years earlier, and I distinctly remember the pub a couple of blocks from where I moved in 1987 that featured 40 different beers on tap. Many of these were micro brews. This was a few years after I had completed an “around the world in 80 beers” challange at a bar in my college town. The thing is there weren’t that many first graders around to know this was happening. My own kids who are young teens may not know about brewpubs. I would also guess that most college kids today still mainly drink Bud and Miller.
I do agree that micro brews and imports burst on to the scene but the timing of when one percieves it could vary on ones age.
My own contribution to this would be specialty hot sauces. When I was growing up Mom had Tobasco and Franks Red Hot. Either one was used very sparingly in “exotic” dishes like Tacos (yes I was raised in the midwest). Now I can choose from 100 different varieties of “death inducing” sauces.
Flour tortillas, used in ‘wraps’. Just a few years and they are everywhere - saw a commercial for BK or McD’s, they are actually selling burger bitz, pickles, cheese etc. wrapped in wraps. That ain’t right!..Mediterranean munchies - 20 kinds of black olives, feta cheese, hummus - it’s in every grocery store, in a stand alone bar or in the deli.
Here, in my lifetime I’ve seen chicken goujons, spicy potato wedges, breakfast rolls, paninis, bagels, the California food mentioned upthread all become extremely popular where before they just didn’t really exist. Other foods have gone out of fashion. You don’t seem to get Blackforest Gateau or Chicken Maryland on menus as often, whereas 20 years ago they were ubiquitous.
Chicken Maryland is at the very least rare in Maryland. I had never seen it on a menu in Maryland when I encountered it on one in England twenty years ago. It’s either an old-fashioned dish that hasn’t been common for decades or possibly one limited to the Eastern Shore: