That's because the Python community is too nice.
When Ruby or node broke compat, they just said "move or die". People moved.
When Python broke compat, they gave 7 years. People screamed, cried, complained, sweared it was impossible for them, that life was hard and the PSF was unfair.
They got an extension of 5 more years.
People still complained !
Hell, famous authors resented python 3 for years, refusing publicly to update their book.
On the other hand, the PSF had a very small budget, only few tiny donations and contributions by people or big companies that were saying they couldn't migrate that their lines of code. The same code that were making them a living, from a 25 years old amazing tech given to them for free.
My take on this is that if you are doing an open source project with a lot of volunteer work, don't be too nice. People have a tendency to abuse it. Save yourself trouble, and balance respect with users and convenience for you.