from __future__ import division
I can see where it falls flat on its face when you're trying to migrate a monolithic 6000-line script. But, IMO, that example falls flat on its face when used as a rhetorical device. If you've got a monolithic 6000-line script with (presumably) no test coverage, you've made your own bed, and I don't think that the inherent difficulties of maintaining something like that should be blamed exclusively on the 2->3 transition.
I once was getting paid double my previous salary to maintain Visual Basic code which makes this 6000-line script look like well structured fully tested object oriented code. When my boss came in to the room and said the project was cancelled, I let out a sigh of relief that I would never have to look at that code again.
In terms of Python2, it will be maintained until at least 2024 because it’s part of CentOS/RHEL 7. I think it will be maintained until 2029 because I saw that package in CentOS 8, but I do not recall if it’s a core package with a guaranteed 2029 EOL.
So using rhel8 won't be a solution. Rhel developers are probably eager to drop Python 2 support as soon as possible. Which is when rhel7 goes EOL. Of course, it wouldn't particularly surprise me if customer pressure makes them support it for longer.