The switching cost is considerable and not realistically achievable for anyone that has embraced the Google world beyond email.
I would have to migrate:
* Android app purchases.
* Android apps that use the Google account for identity.
* Data in Google Fit
* Data in Google Maps including reviews and ratings of restaurants and places visited (which I find useful when I re-visit a city)
* Data in Google Calendars
* Address that others use for Calendar invites
* Address that others use for Google Drive shared folders
* Google Drive data, including configuration of permissions on folder access
* Google Photos, including configuration of permissions. These are photos going back to 1996, 100k+ photos.
* Browser sync
* Browser stored data, passwords and autofill
* Android backup
* Google Keep
* Group memberships
* Group ownerships, and somehow move those groups
* YouTube videos uploaded, and preferences
* Android TV apps and configuration
All of that, is just what I have on my Google Account that is on a Google Hosted domain.
And even if it were possible to somehow migrate that... I would most definitely lose all of the history that so much of that represents. i.e. Google Fit history, Maps Timeline history and so on.
Others may have it worse than I, I haven't got anything in Google+.
All of this works, and it works really well. It's a great offering, and I'm a much happier consumer paying for this than not.
But... it's silo'd. Even intra-family every one of us has our own account.
We were really hoping that Google Hosted gave us a path to treat our family as an organisation and to share within... but that's not how it's panned out.
So we've been hoping that Play Music for Families represents the ability to create a shared group for the family, just a group with a couple of accounts, and these can share stuff. Starting with Music, but hopefully eventually reaching Photos, TV, Video, etc.
Instead it does look like the definition of "Family" is "Gmail accounts", not "a small group of immediately related individuals"... and in that latter definition, who cares whether an individual has a Google Hosted account?