Microsoft specifically cared about all that, way more than 20 years ago - Windows, for all the criticism it takes, from early days had internationalisation (they wanted to sell across the world after all), accessibility features, ways to adapt to different screen and DPI sizes etc. I think Explorer windows since at least Win 98 did something responsive-ish in that various side bars/panels would disappear if you made the window narrow enough. Of course, the icons would rearrange themselves into fewer or more columns as you resized the window too.

I would expect some overhead, but none of the features you describe seem to justify performance hit apps have taken.