I know you’re applying the same model as for SSH keys (and functionally they are very similar) … but I also think 1 SSH key/device is impractical if you have many services to log into and many devices to log in from - which is just the reality nowadays.
Imagine having to use a specific password for each service/device combination.
Instead we don’t tie passwords to devices, but to users, to avoid this complexity.
It's not particularly impractical for SSH: have a text document with the public keys of all your devices, and copy it into the authorized keys for any system you want to log into. Passkeys don't have an analog for this, though.
> Imagine having to use a specific password for each service/device combination. Instead we don’t tie passwords to devices, but to users, to avoid this complexity.
But that is the entire premise of Passkeys—they remove the complexity, because having individual passwords per device is clearly superior to user-bound passwords, if you don’t need to worry about it and it just works. Hence why, to stay with SSH, you shouldn’t use SSH keypairs, but certificates signed by a CA.
Fwiw, I have two phones (work and personal), two tablets (ipad and Android), 4 laptops (primary employer, client, personal, music productions), one main desktop for gaming, 4 intel nuc for various TV's and whatnot around the house and two Intel nuc for experimenting. Plus my wifes stuff.
Everything but employer stuff was cheap on Facebook marketplace. I am a bit on the tail end of my friends and coworkers but not by much. It's always been supremely convenient to be able to choose the form and location of my computing device. The cheap devices are largely disposable - I have several layers of backups. It is this perspective that makes passkeys seem strange, a Cartesian joint of many-to-many between my devices and providers that quickly gets... insane.
(This is in context of Passkeys. If your question is ssh, substantially less:)
Imagine having to use a specific password for each service/device combination. Instead we don’t tie passwords to devices, but to users, to avoid this complexity.