I can say you're going to be wrong ;-) Lots of sites are adopting it through services like CloudFlare and large shared ISPs will likely turn it on as a feature (or for all users) once the Apache/Nginx pagespeed plugins stabilize and SSL grows cheaper thanks to IPv6 addresses. The main problem is that SPDY adoption basically goes hand-in-hand with SSL adoption, and SSL hasn't taken off though it should. You wouldn't say SSL has failed, would you? ;-)