I think the app management, specifically the act of killing off background apps, is just too enjoyable of a thing to do (swipe up to send bits to the nevermore).
The biggest problem my crazy brain finds with background apps is when I am looking to navigate between them. Every historically launched app is there 'in the way' such that I feel compelled to kill off everything but my most consistently used apps (mail, podcasts, browser, etc) so they're easily accessible.
I know that the suggested route here is to put these apps on my home screen (which I do), but I'm somewhat obsessive about keeping things clean there, and find it oddly more time consuming to close the app, hunt and peck through rows of icons than it is to double-tap, so I tend to rely on the app switching UI.
Feels like iOS should know enough to know which are my top used apps and to keep those 'in front' of the lesser used ones, in which case I may not feel so inclined to force quit everything to keep it 'clean'.
Or, split the app switching UI from the "this is where I go to kill apps in a fun and satisfying way" UI.
Opportunities are usually disguised as hard work, so most people don't recognize them.