Python 3 has not "replaced" Python 2. The reality is quite a bit more nuanced than this, and it is hardly a bad thing that Django does not support Python 3 right now. To give this section the heading of "The great divide" is just a tiny bit hyperbolic.
From the top of the python.org page dedicated to the subject[1]:
Python 2.x is the status quo, Python 3.x is the shiny new thing
Also from that same page, here are some of the key things in Python 3 that are not in Python 2 yet:
* function annotations
* syntax for keyword-only arguments
* extended tuple unpacking
* non-local variable declarations
There is nothing in this list that a developer must have in order to develop their app, and there are no Python 3 exclusive projects that do not work with Python 2.
The fact that few major Python projects are currently ported to Python 3 is not evidence of some tremendous looming problem in the Python language. It is evidence that Python 3 is only, really, an evolutionary transition from Python 2 and that this transition has a long time horizon.
The move from Python 2 to Python 3 is nothing like the move from Ruby 1.8 to Ruby 1.9. There are no dramatic speed or stability improvements that make Python 3 something that is terrible to miss out on, and there is no rush to get projects ported to Python 3. It will happen when it happens.