On Android, there is termux terminal emulator, which allows to run native Linux binaries and already has many packages. Arguably there were other ways also before termux existed: GNURoot Debian was an app that ran a minimal Debian chroot in fake root (`proot`), Before that there was KBox. In termux also I run a full Debian chroot using proot. None of this requires root.

Even without that, static binaries could run till some recent version. I have poked with dynamic loading and LD_PRELOAD to set up my own environment which could run most Debian packages using libfakechroot && libfakeroot.

People like to shit on Android. But in terms of power user freedom, apple doesn't even come near.