This has been a long time coming. Not being able to use Python3.x for web development was a large barrier for me switching completely. Now Python3.x just needs to be the default for more linux distros.
It is the usual chicken and egg problem. Distros won't upgrade if there is no reason to. In fact, many are reluctant to upgrade to 3.0 since it breaks a few mini-apps developed in 2.x (as happened to me on ArchBang Linux a few weeks ago).
You need a killer app to force through the migration. Viz Rails and the number of hosts who now have Ruby hosting (if only in name) even on their cheapest hosting packages.
The larger problem is that all the existing killer apps need porting over first. Python has a large ecosystem of killer apps (or rather libraries) already, so no matter how killer your new app is, it probably won't outkill the sum total of all existing killer apps.