Comment by jamesboehmer

It may partially be because of vendor lock-in, but I think the real reason is security. For example with Apple's Secure Enclave hardware, you give secret-generation responsibility to this chip, and can never see the value. I use it for SSH private keys, which are meant to be disposable/changeable. As much as I want to own and control all my data, I personally think this is pretty good footgun protection, and I'm ok with being unable to export my passkeys from 1password (and for the record, 1password does not prohibit TOTP exports).