You say such an user-scenario is an absolute edge-case. I don't buy it. If it's such an edge case, why the change in licensing then?

They're not changing the licensing for OEMs or subscription. They're withdrawing the licensing for permanent ownership of shrinked wrapped copies because, why bother paying for all of the infrastructure to maintain it if people aren't using it, and it's expensive to maintain? And if you've withdrawn that option, why keep text in the EULA that only relates to options you no longer support?

I don't see this is a "let's tie everyone into buying new versions of Office every year", I see it more as a "Google Chrome, Firefox and all of Apple only have to support one version (the latest) of their software, and yet we're supporting versions that are nearly a decade out of date - which makes it expensive for businesses to upgrade (because they become dependent on the product), and expensive to fix (because we have to security fix the product multiple times for every vulnerability we find) and it's expensive to support (because we have to train customer support how to do stuff in the customer's version of Office).

It feels much more like "let's try pushing people into updating more quickly so we can avoid some or all of that cost, because we have horrendous overheads that none of our competitors have, and that's not translating into profits."

It might be a little bit evil, but it's still orders of magnitude less evil than everyone else in the industry. Nobody else supports anything other than the latest version of anything these days.