The bottom line
(For the record, I'm not a Microsoft basher. I have Windows 7 on both my laptop and my desktop. I upgraded both computers to Windows 10, and I reverted both in less than an hour, My negative reaction to that OS is based on personal experience.)
At some point, when the thrill of "Wow -- it's free!" wears off, and frustration settles in, people are gonna finally realize that Microsoft is not a philanthropic foundation.
Windows 10 is a bare-bones OS. Microsoft is pushing Windows 10, because they intend to make money in the future by charging for add-ons that were included in Windows 7 and 8.X.
On the other hand, Windows 10 includes -- also free of charge -- "features" missing from your old OS, such as
endless loops
missing drivers
software incompatibilities
NSA-class privacy intrusions
In short, beware of geeks bearing gifts.