Ran across an interesting article yesterday Windows 10 may be free, but it’s crammed with tricks that make Microsoft money http://www.digitaltrends.com/computing/windows-10-monetization-free/
Windows is not free though. It's a free upgrade to a version that is designed to sell you stuff and get you to use its browser, apps and store. You will end up buying it when you buy your next (Windows) PC but until then, a lot of us are happy to continue with Win 7.
In fact i rather use some of the Metro Apps (Edge, Weather, Mail, etc...) than 3rd party ones. Metro Apps run in Appcontainer. Now nobody force me to buy metro Apps, i don't even open the Windows Store. as always, but at least i don't have to spend hundreds bucks on that actual machine, as i had to do with Win7
Privacy Implications of Windows 10 https://www.schneier.com/blog/archives/2016/08/privacy_implica.html