What we need is "upwards-compatible". Windows 8 has a kernel that's probably an improvement on Windows 7, but only techies ever notice it. It could have had much the same UI as Windows 7 as "legacy mode" and that ghastly not-Metro interface as "new mode" with a choice between the two made every time one logs in (one click). But oh no - they had to tear up everything that went before, and force everyone to start over. F*** them.
It's not just a user issue either. Talk to someone who writes programs with Windows GUIs about it. If Microsoft cared about its customers, anything that prevented an old MS windows GUI program displaying on a new Windows platform would be called a BUG, and fixed asap.
In the Linux world, things work differently. The Gnome team actually did the same as Microsoft - foisted a radical new UI on their "customers" that they didn't like or want. But it's open source, so someone forked the old source and gave it a new name (Mate) and someone else took the newer version and re-skinned it to be less unlike the old version (Cinnamon - which is now also a complete fork). And there were several longstanding alternative UIs out there in the first place - no monopoly on our desktops, thank you!