>most apps don't have any need to access the internet in the first place.
It would severely depend on how you categorize "most apps" because I would say I pretty much only use apps that need the Internet, barring Calculator, Camera, and a PDF reader (only because I prefer how it zooms books vs browser. Everything else implicitly needs the Internet as that app is just a better UI to using their mobile web site, if they even offer one.
Apps are more than just a gateway to content. Your phone is also useful as a tool in itself. Most health, hardware, creative, and productivity apps do not need access to the internet. Even downloading, say, content packs could be done via icloud if apple cared about privacy. Syncing with icloud and not some rando company's probably insecure webapp is a great deal of the appeal of an app store in the first place.