It's not *that* hard to prosper with even a vegan diet in the modern world, I know several who do fine.

Hardest part is knowing implicit animal ingredients you might not otherwise guess, which almost tripped me up when I visited the US and (as a vegetarian*) almost bought some yogurt before reading the ingredients list and finding to my surprise that it contained gelatine.

* it's mainly the cheese; I've substituted out other uses of milk. Also, vegan yogurt is a thing now, not sure when that happened, before or after that visit.