There's a number of quiet warnings in my head that this is too overbroad. Don't get me wrong, I think something like this should happen 100%. But this seems to cast too wide a net.

What about my bank? They have >100M users, and with an app/service portal, they'll be required to be "interoperable". I don't want my bank or my bank info to be interoperable. I also don't want my bank to have an interoperability interface; as an internet plumber, I fully realize the first thing you need to have a blockage is a pipe with something in it.

What about content delivery? Will I be able to play music/movies hosted by my subscription provider through a 3rd party? This calls into question some difficult problems around licensing that may be impossible to satisfy via existing, established contracts; don't paint a content provider into a corner of guaranteed noncompliance.

Where is the definition of "interoperability"?

This will be a field day for an endless bevy of corporate lawyers to say "Oh XYZ isn't a service with users. It's available to users of ABC service, which is fully compliant with the interoperability rules as required by blah blah."

I applaud the effort and think this is a priceless next step in helping define where we should go next, but I'm only hearing possibility and daydreams, not concrete implementation.