Yeah, in the old architecture customers could run smartapps for free in the groovy cloud provided by Samsung. So that encouraged a lot of people to write and share custom smartapps. Plus the original version of routines in the smartthings app were much more limited than they are today, so there was a greater need for custom smartapps.
In the new architecture, the free groovy smartthings cloud Will be shut down, so anyone who wants to use a smartapp has to host it themselves, either through a hosting service or on a local server device. That’s a lot more complicated for nonprogrammers. So there’s a lot less energy going into the creation of custom smartapps right now except, of course, from device manufacturers, although a lot of those are hoping that matter will solve that issue for them.
Anyway, I think there will continue to be a lot of integrations and a lot of different rules options, it’s just most of them won’t be smartapps. For example, see the following thread: