This is such an ignorant and oversimplified argument. The only reason one could assume that it’s the designers at Apple who “need to show impact” instead of PR project management shenanigans is if you’ve never worked with design at a large scale. I’m pretty sure some random designer at Apple has already redesigned something like Mission Control (which has been pretty much unchanged in the last few OS iterations) but it just isn’t the right time to launch said upgrade so it just sits on the back burner for years.