I can't help but wonder, has Apple jumped the shark?
Ever since the release of OS X Yosemite, I have heard complaints about the pinwheel constantly appearing and unresponsive UI. My own experiences on a work machine updated to El Capitan seem to confirm what others are reporting. Using this Mac feels a lot like the old Windows hourglass days.
More recently I updated my wife's iPhone to iOS 9. I did hold off until 9.0.2, but it just didn't seem to matter; iOS 9 is a beta OS that never should have been released. My wife actually said she is ready to throw her phone in the garbage! To put this into perspective, she has had a couple iPod Touches (2nd and 5th gen), and absolutely loves her MacBook Air (still rocking Mavericks). She is a typical Apple fan, and she's just about had enough.
I know it is an oft-used phrase, but I really do doubt the iOS 9 scenario would have "happened under Steve". To be clear, I do not admire Steve Jobs; he was a complete jerk who publicly berated employees. I would never want my child to "grow up to be the next Steve Jobs", but it is exactly because of who he was that, under his reign, it is unlikely we would be living with the glitchy OSes of the New Apple.