Re: It's the data harvesting
"Did you pay for Windows 10? Nope. You paid for Windows 7/8, Windows 10 is NOT an update to 7/8, it's a different OS."
GUI /= OS
Actually, Vista/Win7/8.x/10 are all the SAME underlying OS with different GUI designs. The actual OS nitty gritty under the hood is the same architecture with relatively minor improvements accumulating over time. There were some medium/major improvements to the OS between Vista and 7 to get the bloat down (mainly the Video subsystem by eliminating double buffering, ala presentation mode), but since then, the GUI has been the main thing getting jacked with all this time in order to run the same UI on tablets/desktops.
Lets look at the earlier NT lineage which changed UI at the same time as it changed the underlying OS, and might be the source of your confusion
the NT3.x lineup was the same GUI and OS underneath (and the prototype for the current winOS with ring3 drivers). It was still effectively the microkernel/portable OS/2 that it started development as. BUT, they threw Program Manager on the top instead of Presentation Manager and didn't include compatibility with OS/2 v2 apps when the MS/IBM relationship went sour. (the OS2 1.x subsystem remained in NT until Win2k)
The NT4 through WinXP lineup was the same GUI (mostly) and OS underneath (pushed drivers down into Ring0, ruining processor portability and optimized to single CPU systems, which MS went on to regret in the multi-core era, and had to fix with "Vista" reverting out much of the NT4 lower level mess. Its this era that created much of the issues MS had with trying to get a newer portable device going due to what appears to have been a lot of hardcoded mess in NT4, which in turn generated a lot of their security headaches which persist to this day.). Now GUI wise, it would have been nice if they'd put the W9x GUI on top of NT3.x and kept making underlying improvements going and waited for HW to have caught up.