On the contrary. Passkeys free us from complete dependence on mobile devices (and the telcos that distribute SIM cards) because passkeys can live on any number of desktop computers.
I said "passkeys free us from complete dependence on mobile devices". Complete dependence means not having other options. Passkeys give us other options - all of us, not just those of us who decide to use those options at any moment time.
If most people use their phone for login that's fine. Many people don't even have another device.
What we should push for is passkey export, migration and backup features. The most likely lever that big tech could use for lock-in is making it near impossible to move those passkeys out of their closed ecosystems.