I'm not sure how is W10 different than Android/MacOS. Actually, on Windows you at least can skip the account registration. On mac you can't even get updates if you don't register. Android doesn't even let you use the OS properly without account.
I'm not sure what you mean by this, can you explain further?
I will say, that I've had a couple of Android phones for perhaps 4-5 years now and while I initially did use the bundled OS on my first one, I have never signed in with a Google account.. I use CyanogenMod now on a Nexus S with no Google apps and the phone doesn't seem to be without features that I might desire, indeed there are vast number of developer options that I don't use. Certainly there are third party apps that I know exist that I just can't get (F-Droid is limited sometimes) but that is not really OS functionality in my opinion.
I've used a (company-issued) Sony phone for two years with in a such way, that the only account on the phone was for our Exchange, with built-in E-mail, Calendar, Contacts apps. Granted, the Play Store was not available, Youtube and Maps didn't work, but they were not the reason why I had that phone.