I think in Python's case there was really no compelling reason to burn the bridges between 2 and 3. Burning the bridges should be done when something will be significantly improved.
I write a fair amount of Python 3 and I don't agree at all.
If your concern is that code written for 2.x won't work in the future, it will be some years until 2.7 is no longer getting security fixes etc. The mere existence of 3.x doesn't prevent you from using 2.7.