Passkeys are essentially an API for logging into websites that requires a password manager to use. The end state is that we become completely dependent on our password managers. To avoid a single point of failure, hopefully you own multiple password managers, and they’re on independent devices, and there is a way to sync them.

I'd think it's exactly the same as using a password manager. Yes in theory you could memorize 500 unique passwords or write them down, but no one is doing that.

There are a few things unique to passkeys though. You can register multiple passkeys for the same account so you could in theory have a physical USB key and cloud synced passkeys. Not many people would do this I would think though it would be easier than memorizing every password. There are also data portability specs in progress right now that let you export/import passkeys between services.

But at the end of the day I would suggest that it should be straight up illegal for a company to freeze your account without letting you export your data. It probably actually is by the GDPR. This problem also already exists for email too. If Google bans you, you'll find a lot of your accounts become unusable. Anything with email OTPs wont work, and some services like Discord won't allow updating your email without access to the existing one.