Can you seamlessly migrate your account (your id, followers, and posts) to another host without losing said followers? I think that's the main feature Doctrow is looking for?
What you lose (at least last I checked) are action notifications based on your forwarded handle(s). This mostly doesn't matter, though in my case I have one mildly-viral toot which occasionally gets rediscovered. Missing out on the notifications storm there is mostly feature rather than bug.
For the curious: <https://mastodon.cloud/@dredmorbius/102376653178100454>
If that is true then that probably goes a long way in addressing the concern Doctrow and others have with Bluesky.
edit: According to one article[1] PDS isn't really full federation like what mastodon has. Right now you can only host your own account in your PDS (But they plan to gradually increase that limit to 10, and then more later)[2]. But it's certainly a good start. Not sure if Bluesky will have the capability to block you from reaching your own followers though (say if they ban or suspend your account).
[1] https://www.theverge.com/2024/2/6/24062837/bluesky-drops-inv...