I’d be doing both (except for not having a basement), especially if the disaster I was planning for was an unknown period of reduced food availability which could easily last years.
Canned food can only run out, produce keeps producing.
Unless, in addition to knowing how to garden, you also know how to can.
Yeah. Preparing for a possible blizzard in February is one thing; starting a garden at that point will do you no good whatsoever.
Preparing for possible long-term disruptions to the food supply system is something else altogether.
Though I will note that some of what I eat while comfortably snowed in will be my previous summer’s produce, put up for the winter.
Yes, canned food runs out. You have to keep a decent supply on hand, and eat it periodically so you can replace it with new stock. So better hope that any long disaster takes place during the harvest, except you may not have the electricity or gas needed to can the food.
Other than for fruits and pickles, you’re going to need a pressure canner. Also, the canned food I’d want on hand would never be canned carrots, green beans or peas, it would be baked beans, stew, things that are filling and protein-based.
There are unusual potato varieties you can’t find at supermarkets, but there’s more than standard Idaho white ones. I doubt the Yukon Gold our Kroger sells are noticeably inferior to home-grown Yukon Gold.
I used to grow brussels sprouts. The store-bought ones, if prepared properly, taste as good as what I grew.
Are homegrown turnips and rutabaga superior to store kinds? 
Yes, my grandmother and her sisters came from farms in AR, and moved to St Louis, but carried their knowledge of growing food with them, as well as a tolerance to the hard labor of picking crops (all of them had picked cotton and other things in their home town). Also, they were experts at canning. I recall my grandmother mentioning an orchard near their home in North St Louis County (very very rural at that time), and she could pick the peaches and can them, it was part of the benefits of my grandpa’s job (who ran greenhouses that supplied many of the flowers to St Louis florists at that time). That generation never turned down food opportunities, since many of them lived a type of austere life in the Depression.
No, but you can grow varieties that you typically don’t see even in specialty stores.
We grow these Tokinashi turnips, and they’re really good; sort of like what I imagine a baby turnip would be like, versus the usual big purple & white ones.
I can’t speak to turnips, but the rutabagas I’ve grown are much more tender and less woody or fibrous than the weeks old ones you get at the store that are preserved in food grade wax. Home grown ones, however, are smaller than the commercially grown variety.
Michelle Obama promoted vegetable gardens.
The same article mentions both Jill Biden and Melania Trump (during the first administration) keeping up Michelle Obama’s vegetable garden, and it still exists in some form. It’s surprising it hasn’t been turned into a putting green by now.
Of course, having a White House vegetable garden for show and culinary purposes is a minimal form of promotion of home vegetable gardening.
Incidentally, I just ate our first home-grown tomato of the season. Picked at full ripeness, beautiful to see, with scant flavor (the variety is “Cluster Goliath”). Hopefully, the other varieties we’re growing this year will taste better.
People who had worked in factories for 4 generations had no such knowledge.
The necessity is to do all of the above. A little here and a little there is what will keep you healthy. A good supply of rice and beans will go a long way, but if you can’t also get some garlic and onions and tomatoes you are going to be miserable.
Tomatoes I could preserve, but I’m not growing onions and garlic when I can get a supply of more than I can use all season long at the store for a few bucks.
That’s just fighting the hypothetical.
Probably both parents didn’t work in factories. And even factory workers have hobbies. My grandfather worked in the steel mill, and he had a big backyard garden.