It really isn't Google or MS, etc. It's actually you yourself...and how you manage options in the browser you use. And, if you manage them correctly, the websites which have those hidden fields will not have them filled by your browser.
You make the choices...knowingly or not, and I'm just bringing that to your attention through this article's source...and how to fix it.
While this is true to a point, both Google and MS mine users data. In fact, one doesn't even have to be a Google user to be tracked, watched, etc.... Google Analytics is used by just about every site these days.
And now more than ever, with the advent of Win 10, MS collects user data via apps and other methods built-in to the OS. I'd say Apple and other software companies do it as well, because knowing users habits and etc helps them aim new and other products toward their customers. It's all about money... and how much of ours they can get.
So in reality, Doc, we can set our browsers correctly, but the truth is that Google and MS can and do data mine users information regardless.... because most browsers don't have built-in privacy measures to prevent it. No, one has to use various add-ons to do that, and even then there's no guarantee that information isn't leaked via other means.
As Metallica sing it.... It's Sad But True.