It was Linux that brought me into icon design. I did it pixelart style, manually. So not (good) scalable to different sizes, as was starting back then.
The main thing about windows icon (and overall) "design" as can clearly be seen in TLA is how ridiculously inconsistent it all is. Perspective, shape, colors, level-of-detail, layout, style. It's mind boggling that no-one hit the brakes in Redmond, hired an intern, just to polish out the worst offenders.
I mean, I get the complexity and business flows in place that produce this terrible mess. But in the end the software is packaged as one thing.
Is it their stronghold on the market (monopoly) that makes they can afford not to care? Or did their customers really not care (I mean, I did, and it was one of many things that made me fall in love with Linux back then)