There is not a single implementation from any major provider, including 1Password, that supports moving passkeys across ecosystems. When asked about this 1Password said that they're trying to lobby FIDO to support a migration spec but they don't have any timeline.
It's not that the arguments have been debunked, it's that advocates seem to almost purposefully misunderstand what people mean when they talk about attestation, portability, and account recovery. Registering multiple devices isn't portability. Keeping keys within a single ecosystem isn't portability.
Additionally, advocates ignore the current state of the ecosystem in favor of only talking about what the ecosystem is intended to be. A nontrivial number of services are using passkeys as a 2FA token. As a result, the current state of the ecosystem is that even ignoring the issue with providers, even websites themselves are not presenting a unified vision of what passkeys are intended to be. It borders on misinformation. No one is in alignment about what passkeys are, and multiple problems are being systematically ignored, and saying that the criticism is "debunked" isn't going to change that fact.
It's not that the arguments have been debunked, it's that advocates seem to almost purposefully misunderstand what people mean when they talk about attestation, portability, and account recovery. Registering multiple devices isn't portability. Keeping keys within a single ecosystem isn't portability.
Additionally, advocates ignore the current state of the ecosystem in favor of only talking about what the ecosystem is intended to be. A nontrivial number of services are using passkeys as a 2FA token. As a result, the current state of the ecosystem is that even ignoring the issue with providers, even websites themselves are not presenting a unified vision of what passkeys are intended to be. It borders on misinformation. No one is in alignment about what passkeys are, and multiple problems are being systematically ignored, and saying that the criticism is "debunked" isn't going to change that fact.