@nprofile1q... I believe he addressed these concerns under the sections titled "The Flywheel" and "The Gmail Problem". new apps still end up giving more users to bluesky. and the protocol is designed in such a way that centralization is encouraged.
under "The Chokepoints", he acknowledges you're correct ala blacksky. but that's a huge ask. but they're not fully independent yet and it's hard to believe most would ever be happy with the alts' functionality if bluesky went full adversary re them.