I agree. Python 3 will not see significant uptake till it is the default on most 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.