I turn Cortana off as much as I can as well, and still nearly every single Windows 10 Pro install so far, be it on hardware or in a VM, has gotten ads on the lock screen and in the Start Menu at some point. The only installs that were not affected are not allowed to speak to the internet directly. I don't use Windows as my daily driver, neither at work nor at home. But every time I start up one of the Windows 10s with their creepy features, I'm glad I don't have to put up with this all day.
Maybe it works for other people to continually futz around with the registry, changing values they don't really know what they are good for. But I don't want to feel like I have to fight the OS every time, just to do they same things I get hassle free from other OSes.