Definitely it can feel like restaurants are taking the piss charging the same for a vego main despite much much cheaper ingredients being used.

My partner used to have the same complaints about vego food! The right recipes can be just as filling (a lot you come across incidentally may be designed to be “healthy” and therefore lower calorie). If you’re interested, “Flavour” by Yotam Ottolenghi is full of really excellent vegetarian food which is filling and isn’t very demanding on your cooking skills. But unavoidably, it does take more time to make a passable meal than a meat dish.