[pansa2]

> I can't help but contrast this with the upgrade from Ruby 1.8 to 1.9.

One difference is that upgrading Ruby from 1.8 to 1.9 brought a significant performance increase, whereas going from Python 2.x to early 3.x, performance actually got worse.

AFAICT this was mostly caused by the removal of the machine-word-sized integer type - in Python 3, even 1+1 is calculated using arbitrary-precision integers.

Python 2 => 3 had lots of other problems as well - ultimately they changed just enough to break everyone’s code, but not enough to make upgrading worthwhile.