[015a]

"Now" why? What's changed? There's no demand for it. The market of people who say "I'd switch to iCloud Keychain if only they had better Windows support" is vanishingly small, and at the end of the day Apple doesn't reap revenue from iCloud Keychain anyway so why do they care if you switch?

A more native and higher quality Apple Passwords app for Windows wouldn't even really solve anyone's problems. I don't know the specifics on how the Windows Hello authentication layer works, but my assumption is: Apple can distribute this app, but this app couldn't just make its passkeys natively available to e.g. Chrome on Windows, without a browser extension which would effectively bypass the app anyway. And, Apple already has a Chrome browser extension.

[p0seidon]

That is the next interesting point. At the moment, you are right; there is no third-party password manager support on Windows. However, when they integrate synced passkeys, they might offer that. I think, until now, there has been no strategic value in leveraging access management for customers. Once you have a passkey in your cloud, you have a connection with a website forever (unless you revoke it). The future is an automatic login via passkeys (with user consent, of course).

What changed: Apple & Google want to enter deeper into customer connection and at the same time offer a more secure and convenient authentication for their customers.