All you have to do is get the app into your user account's purchase history. You can do that on a borrowed device and immediately hand that device back to the owner.

...and do that every time for a new app. Again, "all you have to do" is buy a new phone

Apple keeps the OS current on it's devices for twice as many years as most Android device makers. Are we pretending that the sort of person who keeps the same device for up around ten years is the sort of person who constantly loads new apps?