Kudos to moxie and team for building usable free software; it's so much harder to build something that people can use than it is to criticize others' work.
There are many data plans in Europe where SMS are charged at rip off rates, and are something to be avoided. Even just the risk of sending SMS is enough to put anyone off using the application. Especially when competing solutions work as expected - i.e. they will not send SMS at all, ever.
TextSecure certainly seems the best option, but its adoption wouldn't help me a lot (I could migrate my wife, my parents - but I most certainly won't be able to use it beyond that circle) and - I really, really dislike central services for communication. This isn't even a serious trust issue, I do believe that the developers of TextSecure are genuinely offering a great and secure text chat experience (ignoring that other solutions promise the same - Threema et al for example, but TextSecure comes with a lot more credibility and therefor trust). But I like to stay in control of my infrastructure. The xmpp server is the best fit - but the protocol and clients cause some issues and No One™ is using it, so the federation is a moot point.
Unless something drastic changed (or I'm utterly misinformed) you could run your own server - and you'd split the network. The explanation was, as far as I recall, that there's no easy way to route things if all you got is a mobile number as an identifier (So .. on what server is that client? A JID has a host, a mobile number doesn't).
To reiterate: You probably could run your own server. In which case you and the 3-5 people you might convince to use that server would share some infrastructure under your control. You would not be able to send a message to the 6th friend that happens to use TextSecure, but _also_ needs to be on the authentic/real network to chat with his family.
Edit: Partially based on https://twitter.com/moxie/status/438049169052155905