> Every single major password manager supports export.

They all support exporting passwords, but, check your CSV; you won't find any passkeys in the CSV export for Apple, Google, Microsoft, Mozilla, 1Password, or LastPass.

(Bitwarden, Proton Pass, and KeepassXC do support exporting passkeys to CSV, which undermines the phishing protections, at least somewhat. It’s possible to trick you into exporting your passkeys from Bitwarden and sending the file to an attacker. It’s up to you to decide whether protecting yourself from being tricked into exporting your passkeys is worth sacrificing your ability to read them.)

> How useful is your firefox passwords on an iphone?

Did you try it? That's the primary feature of the Firefox app for iPhone.

(Especially since the Firefox app for iPhone is just Safari's WebKit wearing a Firefox disguise.)

> Or Mac OS's keychain I use as a daily driver on my windows gaming desktop?

https://apps.microsoft.com/detail/9pktq5699m62?hl=en-US&gl=U...

> With the iCloud for Windows app, you can access photos, files, passwords, and other important information from your iPhone or other Apple devices on your Windows PC.

When Apple's your password manager, you use Apple's password manager app to synchronize passwords and passkeys.

> That's just wrong. I use android, my partner uses ios. If he creates the passkey in safari, it's not going to get synced over to my phone

It would, if the people implementing it weren't all so obsessed with pushing their own platform-specific solutions over enabling open standards. LastPass works fine on Android, iOS, Mac, and Windows, but each one of those platforms defaults to saving passkeys in their own platform-specific store unless you jump through hoops to specifically save them somewhere else.

>That's just wrong. I use android, my partner uses ios. If he creates the passkey in safari,

There. You just violated the premise of his point, that you use a password manager that syncs to all your devices.

> That's just wrong. I use android, my partner uses ios. If he creates the passkey in safari, it's not going to get synced over to my phone. And that's just the first of the family sharing passwords issues. Same person issue is also present if somebody uses an iphone and a windows laptop, or chromebook.

The passkeys sync just fine between iOS and Android on our devices using 1Password.