Have you ever seen the kitchen in a Chinese restaurant?

Obviously, but if single digit percentage of total cooking is done in a wok, it seems like we should just exempt Chinese restaurants and move on.

That would satisfy Chinese restaurants, though I wonder if other restaurants would also ask for exceptions, if for no other reason because they don't want to put in expensive new equipment. Are there other types of cuisine that strongly benefit from gas?

Are you asking for a precise number? Sorry but what kind of question is that? I couldn't even give you an order of magnitude but it's a lot. Basically every person who is cooking an Asian cuisine.

Woks are not commonplace in probably at least half of Asia, but your point otherwise stands given the popularity of wok-using cuisines alone.

And many who aren't. Woks are incredibly useful for frying anything mixed.