thing is that you're completely ignoring how culturally important meat is to a lot of people, and how much easier it is to cook a very tasty and nutritious meal with meat.

sure, rice and beans is cheaper, but you need to eat other things too and to most people "rice and beans" sounds like abject misery.

You can't just say "go vegan" as if that's just a switch you flip, the easy vegan alternatives are expensive and the cheap ones aren't easy.
If you want people to go vegan, start producing cheap and easy vegan food that is indistinguishable from non-vegan stuff, we have a small amount of such products here and it's helped me eat less meat.