The amount of churn in the computer industry is staggering and the upgrade treadmill is a huge waste of resources to many, but I suppose it's the only way for them to continue making a profit. Personally, I think Windows as an OS reached its pinnacle sometime around the XP timeframe; since then it has mostly been frustrating UI changes and feature removals, "security" features designed to lock down your PC against you and instead follow the commands of some corporate entity, and massive amounts of data collection. Incidentally, that timeframe coincides with the rise of file sharing, and while the Internet certainly wasn't very safe or secure back then, it was an era of relative freedom.
I was quite disgusted when I saw that Windows 10's start menu contains adverts; maybe Microsoft realised that the average user would likely install adware themselves anyway, so they wanted to get into that industry too... all the evidence certainly supports that, including the now-well-known closing the upgrade window indicates consent shady behaviour common amongst malware/adware. It's clear that MS is really, really desperate to get as much users onto Win10 as they can.
To adopt a phrase MS originally used against Linux, "Windows 10 is a free upgrade only if your freedom and privacy are worth nothing."