Earlier quoted context omitted.
The point was that once people are looking at restructuring the code base and re-writing parts of it, it also becomes a point of evaluation other technologies and frameworks. So there is a high chance many will not switch Python 2 -> Python 3 but Python 2 -> Go or something else. Then well ok, the answer to "What did Python 3 bring to the Python community?" becomes "Yeah it ended up driving a lot of people away", whi…
So switching Python 2 -> Python 3 is a higher cost than Python 2 -> Go?!?
It's also quite an issue for COTS software - sometimes to jump forwards and clean up APIs they have to do a huge refactor, sometime even a re-write of the API. If this is troublesome enough, it's worth taking the time to look into the competition.