> ... nobody wants to take care of things anymore ...
I mean, why would you? It is quite a bit of technical hassle, even for an experienced admin. There's quite a bit of cognitive load just deciding what software stack to use, even before you run an installer. And then you have to maintain it too!
Compare that to less than 3 minutes of sign-up and creation of a new subreddit. It is an orders of magnitude difference in effort and knowledge required.
You're talking about late 90's-early 00's tech there (basically, LAMP architecture). It wouldn't be that hard to develop an open source, generic hierarchical forum engine that would be easier to deploy than an Apache+PHP+MySQL suite from scratch (on a dedicated Linux server that you have to completely configure all by yourself), and that would work both on a web browser and through a smartphone app.
Security would be less an issue than back then, too. We learned a lot since early PHP and early Javascript's bad practices.
I mean, why would you? It is quite a bit of technical hassle, even for an experienced admin. There's quite a bit of cognitive load just deciding what software stack to use, even before you run an installer. And then you have to maintain it too!
Compare that to less than 3 minutes of sign-up and creation of a new subreddit. It is an orders of magnitude difference in effort and knowledge required.