How is it straightforward? I tried porting a very small codebase from python 2 to 3 and ran into a bunch of issues which required manual workarounds. If it were easy to port, most library owners would have done so already.
I guess it depends on your idea of straight-forward. If you mean, "press a button and everything is done for me," then it's not very straight-forward.
If you want to port there's a well-tested and clear path. There are enough big libraries out there that have managed it. There is no real barrier as the OP suggested in their article.
My belief is that the effort os a linear function of your code base size. This means the larger the code base, the more effort required to port.
Also, porting is made more difficult by the fact that Python is a dynamic language, so a lot of errors that could be caught at compile time will only be catchable through a thorough testing suite. I have seen little evidence to suggest that porting from Python 2 to 3 is actually straightfoward in the sense of not requiring significant effort proportional to the size of the code base.
Believe what you will but the numbers suggest that it's not a technical problem to port a Python code base. It does take effort and work but it's "straight forward" in the sense that what is required is well known.
