Android was always written with the expectation that it would run on a diverse set of hardware.

You could run iPhone 4 apps on iPhone 5 and beyond. But they looked horrible.

Sorry, I think you’re misunderstanding. Android vendors built compatibility layers that allowed 16:9 apps to run on 18:9 and up screens. The apps weren’t built to run on 18:9 screens but the vendors found a way regardless.

Part of what makes iPhones great is that you aren’t running apps sitting on a pile of compatibility hacks. It was all designed to work correct on the exact device you use.

> running apps sitting on a pile of compatibility hacks

You do realise the only reason iphone retina screens became a thing was to enable double pixel scaling because iphone apps at the time were coded to a fixed resolution.

That's the definition of a compatibility hack.

Of course apple being apple they managed to sell it as a feature and made every person who was happy with a 1366x768 laptop suddenly desire a retina display.

What does the user care if there's a "pile of compatibility hacks" there or not, so long as the app still exists and works as it should?

In the case of Apple removing 32 bit support from the OS first and then the actual processors:

- they care about their apps not being evicted from memory as quickly when they switch apps because memory isn’t taken up by 32 bit and 64 bit versions of shared libraries.

- increased battery life by not having as much RAM - yes RAM takes energy.

- using the die space saved by not having 32 bit instruction decoding means you can use that die space for enhancements that users care about, and decrease the die size to make the phone more battery efficient

- for Mac computers, you have computers that are faster, have more than twice the battery life, are more memory efficient (meaning less swap), and can be fanless without getting hot.