Microsoft has made careful and deliberate strategic decisions about Windows 10.
"Look at Google, and Facebook... They're making a killing on all of that personal data and ad targeting info. We need to get in on that. Hmm... We control most of the home PCs, what if we just funnel that info back to our data centers. We make Windows an OS-as-a-Service, then no one can complain about all the telemetry we collect. We get the audio, the webcam, and every keystroke. That's even better than Facebook or Google can do."
"Man! What a jackpot! Let's do it! We have to make sure as many people as possible are running this new version. We can call it a free upgrade, people will sign up for anything if it's free. How can we get it on everyone's machine?..."
* All eyes turn toward Windows Update *
This isn't an "oops, that was a bug", this is "you're going to take this 'upgrade' and like it you filthy little revenue stream."