if milk was not used as a good it would simply be replaced by another. it's not as if everyone in the world uses cow's milk in their food [the majority of them didn't/don't, though due to the american diet spreading [like] a disease, they tend to be more widespread - though most of the people in asia and africa are lactose intolerant iirc. in addition, after the [second?] world war, animal products [of all kinds] were rationed and scarce, whereas plant-based foods were easy to come by. because of this, the women [as they were in the kitchen at the time] got really creative with their cakes and such, and these used little to none of the rationed foods due to their being difficult to come by. not to mention that many foods naturally don't have milk in them, especially plant-based foods [and there are
a lot, it's just that so much of the west depends on MAH MCDONALD'S]. in fact, very little actually does have milk in it if you're not talking about little twinkies or dairy queen shit or whatever.
tldr if you like foreign food, being creative in the kitchen, or not eating heavily-processed cakey things, you're golden. if you're stuck on modern american or european food with chemicals up the ass or cheese then you're sol i guess.