So to be sure, you’d like your Word on Mac to also have a “close window” button as a square “X” on the top right instead of a red circle on the top left?
OS’s are not always 100% internally consistent but every OS vendor is striving towards that.
Finally I agree that the OS should not natively style a web page (although as I said I’m in favor of user overrides). A scroll bar is not a web page. It’s an OS level interface element.
Well, probably not, though even that is debatable (think of the game example). Still, I think the window control elements are pretty close to something the OS should fully control.
On the other hand, I would expect it to use the Ribbon for interaction, and mostly ignore the MacOS global menu bar, so I can still find things where I'm used to them.
Having said all that, scrollbars appear all the time inside other elements of an app, so I don't see why they should be compared to the window close button. If they're smack dab in the middle of my screen, they should look like the rest of the app.
OS’s are not always 100% internally consistent but every OS vendor is striving towards that.
Finally I agree that the OS should not natively style a web page (although as I said I’m in favor of user overrides). A scroll bar is not a web page. It’s an OS level interface element.