They're stuck conforming to an artificial schedule of once a year major releases. They won't let themselves take the time they need to get things right anymore. It's no surprise quality has gone down.
Quality usually don't go up when releasing less frequently, quite the opposite. The more you change things, the more likely you are to have severe bugs. When Apple was releasing major OS upgrades less frequently, you usually had to wait until a .4 or .5 point upgrade to have something usable.
The first release of macOS Sierra (10.12.0) was vastly more usable than the first release of MacOS X Snow Leopard (10.6.0). I should know: I transitioned to Snow Leopard on release and practically nothing was running on it. I think it's the only time in my life I reverted to the previous version of macOS... It didn't prevent Snow Leopard to become one of the best OS, in the end.
The problem is that Apple is shipping things that aren't right/ready, but this should be independent from the release schedule.
At least they had time to reach that .4 or .5 version. Now they pop out a new one before the old one is fixed, and we're stuck in a never-ending cycle of suck.
