It might have taken them a bit longer to get the initial implementation out the door, but it would have avoided all of these discussions, which I'm certain are also impacting WebAuthN/passkey adoption across the web (assuming that the views on passkeys here are at least somewhat representative of technical decisionmakers).
But if the choice is between getting to the status quo via suboptimal intermediate steps or not having WebAuthN and passkeys at all, the former seems much preferable.
There's a lot of users that isn't great for. Especially there are statistically a lot of iOS users that use Windows desktop/laptops that Microsoft and Apple are trying to bridge but don't always have the best UX today. Same for Android and Windows users, there's statistically even more of those.
Also, as you can tell from HN comments every time Passkeys come up, HN is full of anecdotes of the craziest mixed device ecosystems people can build. We can be a loud set of users, and we certainly need the most convincing that our "power user" needs are met for all of our complexity requirements.
> anecdotes of the craziest mixed device ecosystems people can build
All it takes is for somebody to use both an iPad and an Android phone. iPads are relatively cheap (cheaper than many Windows laptops!); iPhones are quite expensive. That's a lot of users right there, and I think it must be at least as common as Windows + iOS users.
However, they fumbled the introduction by trying the “maximum vendor lock” approach first. Now they need to convince everyone otherwise, even if technically it’s open now.