That's NOT true. Most windows on the macOS have round corners. If I had to bet, I think the trend will get bigger - the corners will be bigger, similar to iOS. The resolution is finer, the display frames are getting smaller and I assume that no one will want a prickly laptop in a backpack, on his lap, in bed...

With the M1 chip, you can run iOS apps on your Mac. And guess what the corners looks a like?

https://graphicdesign.stackexchange.com/a/18690

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