Yes, if there are 5 boys and 5 girls in each class in each house that makes 70 per house and 280 altogether. Maybe they have a lot of alumni come for the Quidditch matches.
The attraction for me, besides the humor and adventure, is that Rowling has created a whole world that you walk into with Harry when he goes to Hogwarts. Maybe not as detailed as LOTR, but just as complete.
Besides, who doesn't want to do magic? I always admired the way Molly Weasley could wave her wand and the dishes would wash themselves.