It's worth noting, however, that desktop and laptop PCs have a surplus of energy relative to mobile phones, so it's no big deal if there's a bunch of processes running in the background doing their thing… usually, anyway, because on PCs it's also shockingly common for background processes to misbehave and consume far more resources than they have any right to. Point in case, the daemon for my Logitech mouse will sometimes consume 120% CPU for no apparent reason for extended periods if I allow it to run.
I could see an argument for extending background capabilities in iOS while also heavily also reducing their potential for bad behavior, though. For example, allowing apps to run in the background indefinitely, but on low power cores only with heavily capped CPU and memory consumption, along with a new Settings page that shows a list of persistent background processes and gives the user direct control over them.