>What a load of bollocks. For new projects this only matters if libraries aren't ported, which they are for the most part. For old projects, either you're in a situation where you can spend time porting your code to Python 3, or you don't; but as TFA mentioned pep-404, the writing has been officially on the wall ever since 2011 so at that point you have to admit you did choose to incur tech debt and do nothing about it, so the claimed loss of productivity is on you.

I call BS (to counter your "bollocks").

Whether the "writing was on the wall" or not, doesn't change the fact that people had to actively port their old code if they wanted it to run on 3.

Sometimes that code could run into the tens of thousands (or even millions for large companies) of lines.

And why would they do it (and at a great cost and time effort)? For the marginal improvements Python 3 brings?

The "writing has been on the wall" is not an excuse, it's mostly blackmail ("port or else you wont run on 3, and we'll stop the 2.x line"). And most people didn't (and shouldn't) fall for that.