I think the world needs more intelligent folks like yourself who have a healthy amount of skepticism. I myself actually consider myself a proponent of these decentralized social networks, and I'm placing plenty of faith on these open networks...Though i don't go in blindly assuming the entire world will eventually adopt these. For me, if i can get my family and friends at least interacting with me - whether through my network or through a pass-through between the 2 systems - that's enough for me. Much like your email example i agree that most will use some free offering because of ease of use, etc. However, there are folks like myself who do wish to host our own...but the expectation - much like email - is to ensure interaction is as seamless as possible between the proprietary and the open networks. I use Gnu Social for now...my hope is that if this stack (Gnu social) fails, i hope it fails fast, just so that the next evolution - whatever that open platform might be - could iterate and progress faster, again with the goal of ease of use/implementation, more seamless integration (between networks), etc.