You miss the possibility that when all the compatibility problems start to happen, a possible organic adoption (by other than hobbyists) would be hampered.
At the same time, hobbyists that could be joining the network because of their initial ethos, would also refrain from joining given the blur and dilution of its values.
What I'm saying is that hobbyists (like me) that develop fediverse software will probably be there _after_ meta gets bored and finds reasons to drop out, which is pretty much what happened to XMPP. And that it does not mean the death of anything.