I can kinda understand Office. Tons of commands, you grew up using the menu bar to access them, etc. It's hard to change.
But for browsers? I'm genuinly curious what menu bar commands you're hitting in a browser on a daily basis. There can't be that many. Grouping them all under one menu button to simplify things and free up screen real-estate isn't that big of a deal.
Until there's an option to turn on the menu bar, Office and Chrome (and everything which mimicks their mistakes) have no place on my machines.