> How screwed are they if everything was in iCloud, vs they were using 1Password/{own,next}Cloud/Evernote/Meta/Dropbox/web apps...?
That would be a more appropriate picture.
> How screwed are they
Not much. Annoyed maybe but as long as they have access to their email and phone number they can reset their passwords.
What about the other way around? If a person broke their Android phone and a friend convinces them to move to Apple? You could argue that then they may have everything in Google and that they could log in on an Apple device with their Google account and use Chrome and Gmail and whatnot, but then they'd be storing everything in Google.
What if Google sunsets a product? Or Google unilaterally decides to close their account overnight with no human in reach for support?
I'm all for interoperability. I do get the risks at hand. But the hodgepodge of separate solutions forming a duct-tape held system is hardly usable for the "mere mortal", let alone integrating the together in reliable ways.
People want technology to disappear so they can go on with their lives and do stuff that matters to them (which integrating platform-independent third party solutions is not). So "all eggs in same basket" is an extremely valuable feature for most.
