I think you're conflating the median North American vegetarian with the median vegan. Your comment makes a lot more sense if I substitute "vegan" for wherever you've used "vegetarian". If you do indeed mean "vegetarian", then I think it makes much less sense in contemporary America, for example.
Yes, almost every vegan I've known is optimizing to minimize animal "cruelty", defined on their own ideological terms. Meanwhile, almost every vegetarian I've known is either one for religious reasons (and have their tradition's cultural cuisines to draw from) or simply don't like meat. I also know many Muslims who avoid meat at restaurants since it's not halal. I am struggling to recall any vegetarians that eat an average American diet by simply replacing meat with something like tofu.
If your intent is indeed to refer to vegetarians, I think that hasn't been the case in the US since perhaps the 90s. American vegetarianism really took off in the cultural context of the 60s and 70s, where Eastern ideas & sensibilities were imported but not the people or their cuisines. If a median American in the 70s wanted to maintain a meat free diet, their options were genuinely restricted. That's certainly not the case now, where the median American vegetarian is likely of recent immigrant descent, and has their heritage cuisine to inspire vegetarian meals. Changes to American immigration policy and the segment of countries where immigrants have come from have changed American vegetarianism. I also think something like Impossible burgers have very little appeal to the median vegetarian, since they're not interested in the taste of meat to begin with.
Yes, unlike the median American vegetarian, the median American vegan tends to appear spontaneously among families that are not themselves vegan. Unlike vegetarians, they don't have a rich family tradition to draw from, and plenty learn to just wing it. That said, I do think even this is likely not the case anymore. Today, in any big city, good vegan/vegetarian food is easy to find. As an illustrative example, I asked a relative who's lived in NYC for 40 years what his favorite restaurant meal has been (he absolutely loves steak). His favorite restaurant is a vegan Korean BBQ. Similarly, I've been informed by Mexicans of an amazing Mexican vegan place in Brooklyn.