Earlier quoted context omitted.
A password manager let's me use my service specific credential from any device, securely and decentralized. Passkeys lock into a specific device and seem easy until you need to use another device. But instead of being a credential you own and control, across what could even be a local password manager, it's one password to everything. Maybe it is more secure than a regular password in some cases but it largely seems…
it's one password to everything You are entirely mistaken. Passkeys involve a third party storing a public key on their infrastructure, while you hold the private half of the key, somewhere. Passkeys are never reused. Even for the same person, they are always unique across websites, and across devices.
and I can't use this on any other device by default. My passkey is locked within the browser used to set it up.