> Mint community seems to have some philosophical rejection of it and recommends a reinstall.

I was doing in-place upgrades of Debian in the late 90ies, and they generally went quite smoothly. Not being able to to do that gives me a strong urge to use blunt terms like "horse shit". In-place upgrades are one of the reasons why you have an advanced package management system in the first place, and abandoning that is a huge step backwards. I do, after all, use this stuff on servers too.