"win 7 and older"? There are still plenty of configuration dialogues that have only seen the slightest of changes since Windows NT 4.0; I'm not exaggregating.

Windows is easily the most visually inconsistent OS out there -- even in comparison to a Linux desktop. That has it reasons of course, many features are in there that didn't need any kind of update in the last 15+ years, therefore their UI was never updated to conform to updated guidelines and so on.