The end result will likely be a few apps that do the legwork to beat the various messaging platforms into some common denominator feature set and give you a single pane of glass.

Unsiloing messaging isn't some quick fix. It would be like saying "we have all these forums like HN, Reddit, Twitter, SpaceHey, Facebook they should all share a global identity system and be able to be used all by a single app with the same APIs." Like we can't even make a generic ActivityPub client.