Exactly.

Almost anything can kinda work on older devices. But lots of little details make the difference between a good experience and a poor one. Which simd instructions did it support. What’s the battery impact on that BT chipset. Did the ANE support NN layer style X?

Apple has a great track record of brining new features to old hardware. I don’t see example here or elsewhere that I think were purely greed and not quality driven.

True, sure. But someone mentioned the canonical example I was thinking of: Stage Manager. That is a 100% software feature that was arbitrarily gated.

Unless I'm mistaken, stage manager requires running 5 apps simultaneously when iPads were previously limited to 1 or 2? That includes 5 render pipelines (way more pixels to push than exist on the physical display). There would be hardware load on pretty much every key piece of hardware (GPU, CPU, memory, caches, disk), and by a non trivial factor.

So why gate it on macOS?

Same reason. Rendering more apps at full screen in real time takes a ton of GPU. Adds ~5x the pixels, and 5x screen scale transforms+effect. All the optimizations for “that’s hidden”/“that’s background” go out the door.