Python 3 has been released in December 2008. A lot of time has passed since then but still today many developers hesitate using Python 3. Even popular frameworks like Django are not compatible with Python 3 yet but still rely on Python 2.

Sure, Python 3 has some incompatibilities to Python 2 and some people need to rely on backwards-compatibility. But hasn't Python 3 been around long enough now for most projects to switch or start with Python 3?

Having two competiting versions has so many drawbacks; two branches need to be maintained, confusion for learners and so on, so why is there such a big hesitation throughout the Python community in switching to Python 3?