Earlier quoted context omitted.
My theory is they made Liquid Glass for the Watch first, where (IMHO) it's actually pretty great, and assumed it would translate well to iOS and macOS, which in retrospect it did not.
Sort of how Microsoft made Windows 8 look like a Zune.
Zune was low key pretty damn solid. (Yes, I lived in Redmond as a teenager.) In fact I may even say it was their last gasp of a solid user interface. Right before Vista.