I was there, then. This was discussed at an unbelievable length, and there was a strong consensus. In particular, the way strings worked in Python 2 could not be fixed in a backward compatible way.

But the process of upgrading was made incredibly smooth. It wasn't just 2to3, or the `six` library: it was that it was easy to write Python files that could work in both 2 and 3, so you could upgrade a big program a single file at a time.

I single-handedly ported three or four fairly large packages belonging to others with literally not one hitch.

And then I watched for years and years as people complained about how impossibly hard it was. Some of my faith in other developers' competence vanished then, never to return.