Python 2.7 was kept very much alive, with a number of small improvements from the 3.x branch backported to it.

Big players, like Django or SQLAlchemy, kept versions both for 2.x and 3.x for quite some time. This allowed for a smooth transition, when all of your dependencies finally had good versions for 3.x.

The difference between Python 2.x and Python 3.x was not dramatic. I would say it was mostly cosmetic up until 3.5 when async landed. Even with these small changes, the splitting of byte strings and character strings alone (an obvious move towards sanity) was plenty annoying for many projects.

Communities and ecosystems are fragile; sharp turns can easily break them.. Even careful maneuvering, like the Python 2 → 3 transition, put very visible strain on the community. A crazy jump that was Perl 6 was not survivable, even though Raku may be a fine language.