Doesn't Django/Python have its own version headaches? (Python 3 came out 5 years ago, but Django didn't officially support until February of this year)
Phasing out old version of the underlying language isn't uncommon. For example, Oracle doesn't even support Java 6 anymore, which was released in 2007.
I think the difference is that Python had a much more realistic plan for the backwards incompatible changes. The fact that the transition will likely take the better part of a decade is a _feature_, not an issue (and there will be supported versions of 2.x throughout that time).
Phasing out old version of the underlying language isn't uncommon. For example, Oracle doesn't even support Java 6 anymore, which was released in 2007.