The truth is, many (or most?) people don't want anything new... When I was working in my brother's restaurant where we were selling ice cream, we had lots of good and different flavors (chestnut, nougat, raspberry...) but people were still ordering their "vanilla-chocolate". Those two are the one I hate the most, lol. Same for pizza, Regina or 4-cheeses or "kebab"...
A part of this behavior can be explained by the fact that usually, in France - at least in countryside/small cities, families don't go out that often (maybe once a month?), so when they do, they don't want to take "risk" as you guys said above.
Then, once you've been to a certain type of restaurant (Asian, Mexican, Italian...) and enjoyed one of their foods, you'll want to find it again next time you visit the same type of restaurant ("hey, last time I had some spicy XX, do you make it here too?").