It's a loosing game to use "open" web solutions to provide a third party application to these silos. Twitter already killed themselves this way (they're just too big to die quickly), and I think facebook will too.
Facebook as "facebook" is useful and fun, and a way to connect with people and share stuff. Facebook as "messenger" is phone service. It's infrastructure that's part of your life. It's part of direct human contact. It's way too risky to trust to an entity like Facebook (or Google).
If these companies had "invented" email, we'd been set back decades. Just look at how badly MS manages to preform as a netcitizen with Exchange and Outlook (for no good technical reason). Without the network effect and competition that the open email standards push, we'd all be faxing print-outs between hobbled messaging silos.
I mean, we're still using SMS. SMS! Because the big boys couldn't agree to just have user@facebook talk to user@outlook and user@google or user@apple in a sane way! Both FB and Google even had XMPP going for a while, but didn't even federate with each other. It's as if Gmail suddenly stopped accepting external mail (not that their magic black holing isn't annoying enough to work around as it is).
I agree completely with you on this matter and this change will probably bring me back to using SMS and email more.
I really hope RCS will catch on in the future, but there are extra obstacles in addition of all these competing corporate silos of this happening - carriers. Depressing.
