a bunch of centralized platforms?

This is what decentralized means. If your home instance goes to shit, you can just move your account to another one.

“I used a hammer to screw screws and it didn’t work.”

ChatGPT is a generative language model. It was not built for this kind of use case, it was not ever intended for this kind of use case, and the fact that it doesn’t succeed at this is like saying that it can’t make you a pizza. The only logical response is “well yeah, what did you expect it to do?”