There's other syndication models, although POSSE gets talked about most.
If you don't want to get your own domain and run a server (not practical for most people) you can still protect yourself from being stuck in a single silo by broadcasting to many social media sites.
There's an ATProto project the main blog sites are working together on around distribution and syndication. It also has places for the off-protocol sites people post or publish.
And the atproto is pesetas right? You publish to bluesky or whatever and the content is replicated to your pds. I recognize the minor difference, but if you have the energy and wherewithal to orchestrate pesetas across silos, surely you can setup a pds elsewhere.