16-year user here. Its been a long time coming, I've watched my friend spiral into a bad place and call me an idiot for being concerned. There is no saving these old networks. They will be around as bullhorns of whoever pays for them but even with the different usability I think its only a matter of time before people start to see "True Reddit" style material coming out of the fediverse and things start to grow less due to thee circumstancesbut more for the same reasons reddit and slashdot before them grew to begin with.
Even IF these networks never fall, no original social network was predicated on the idea that it MUST be for everyone. Thinking it needs to be is just monopoly enabler talk IMO.