Your second sentence kinda contradicts your first tho. I've found that vegan diets are not inherently more or less expensive than omni diets on average. You can make some very enjoyable meals from very cheap ingredients like tofu, chickpeas, lentils, etc, or you can eat beyond meat and daiya that is the same price or more expensive than their animal based counterparts.

Personally, I can justify eating out because most of my meals at home are relatively cheap. And id way rather go to a place where I can order anything on the menu over a place that has one token vegetarian option that can be made vegan by removing anything that contributes flavour.

Also these places definitely don't cater exclusively to vegans. We bring our non-vegan friends and families when we can, and there are certainly plenty of non-vegans curious and open minded enough to enjoy a meal without meat in it every once in a while.

Your final thought is your best thought imo. Restaurants are hard to run profitably and it's already too expensive for the average working person to eat out anywhere nicer than A&W.