It's pretty easy to build a tool or game that a few hundred people can get value out of though right?
No, because there's this weird thing about developing apps.
If you have too few users, this means that you can't afford to eat, while too many users means that other app developers can't afford to eat.
It's much cheaper to open a restaurant, then build a word processor that someone can get value out of. It's much harder to build your restaurant chain to serve 100,000 people, then it is to scale your word processor, that can serve 100 people, to serve 100,000 people.