This could be a case study on how design at Apple has gotten worse. Take iTunes/Music for Mac:
1. From Catalina on, full-height sidebars started eating into valuable toolbar real estate.
2. In Tahoe, not only to stupid big corner radii eats more into you usable area, they now allow the inspector sidebars to cut even more into toolbar space.
3. The volume & scrub controls are now an extra click away.
Just compare these newer UIs to #iTunes from 2010. Full-width, excellent use of space.

