It is risk aversion in low level managers, and profit margins in high level managers, and since they're the market leader in the US and smartphones are pretty mature there's little risk of anyone jumping ship (go to android, start over, lose all your apps, get differently frustrating issues).

They don't have a Steve Jobs anymore to sit down with the product, get frustrated beyond belief with it, and start sticking boots up asses on general principle.

Nobody is going to step up to do that because all the other executives would hate them for it and knife them in the back, and it would be seen as a waste of effort. And nobody could ever tie fixing those bugs to making a financial number go up, and would argue instead that it was pure cost for no benefit.