The people I know who use Python, including myself, range from utter beginners to experienced programmers, but are using a relatively small subset of the available libraries, and are just using whichever version we started with. I could translate my code to version 3 in a heartbeat, but have no particular reason to do so. I've translated some of my most important stuff from BASIC to Python after all.
Professional developers will do whatever is right for their projects.
My concern would be for the folks who develop and maintain the libraries -- for whose generosity I'm grateful. If there were some sort of consensus on the direction of Python, I'd hop on the bus just to make life easier for those developers. Their time would be better spent adding useful features or just combing the code for bugs, than coping with multiple Python versions.
Could a single Python interpreter somehow manage a mixture of 2 and 3 code?