My wife grew up with terrible cooks. So did I, but I learned to cook to make my own food, she resorted to microwaves, frozen pizzas, and 2 (in my opinion extremely bland but will never say because she was super happy to make it for me) dishes she figured out.

Since being with me, she has figured out she likes chicken, salmon and tilapia, medium steak, a few vegetables, and quite a few other things. Her parents UNDERCOOKED chicken and seafood, made steak into charcoal or still bloody with no in between which made her not trust any pink, and they boiled the everloving shit out of every vegetable until peas were mush and broccoli looked like it was rotting.

They also never had real mayonnaise, and she only ever had miracle whip and thought she hated mayo.

And tea was always super weak and filled with sugar, so she never had real tea until she tried mine one day and went "I thought you said this was tea?"

Total speculation: I think the reason so many of our parents suck at cooking is because they didn't learn before having kids, and when it came time to either spend shitloads on carryout or figure out cooking, they just remembered the basic ingredients from their own childhood, but we're never around for the spices or cook times. And since internet wasn't really a "I need a recipe, let me google that on my phone real quick" until much later, it was that or find a cookbook with all your favorite recipes.