You listed all these extra things you have to do on Andriod just to be able to get a timely update. On iOS it's one step.
And everything I've read these past few weeks says iOS is still smoother and more reliable than Android.
Besides, you're mostly comparing iOS 7/8/9 to iOS 6 from 2012. If you look at the features added to iOS in that 3 year period AND the bigger number of devices that iOS 9 is supporting, I think the advantages far outweigh the disadvantages.
With some people, Apple can't win. If they work hard to support as many older devices as possible, people complain about how bad iOS 9 runs and Apple is forcing them to upgrade to a newer phone. If Apple didn't support older devices people would still complain that Apple is forcing them to get newer devices.
I'm all for having a great experience on my phone and I don't think I would settle for a product that gets worse every year. Is iOS 9 buggy for some folks? Yes. But Name ONE OS that works perfectly for every customer. You won't find it. Because people run different apps, and have different usage patterns. All those things will most definitely affect the performance of the OS.