It's easy to get your own code to run on 3.x. The challenge is making sure all your C library dependencies run on it. And Python is nothing without its vast library ecosystem.
I also provide binaries for all the Python versions in both 32 bit and 64 bit (where relevant) for Windows. When hosted on Google Code, their download stats showed the vast majority on Python 2.7 32 bit with a slow increase in 2.7 64 bit. Python 3.x downloads were roughly similar to Python 2.4 downloads! Sadly since moving to Github I have no idea what the download rates are.
BTW the only reason for not supporting Python 3.0 was that the test suite needed a module that wasn't provided (base64 or something similar), which I could have worked around, but the 3.0 release was end of lifed so I didn't bother.