Apple's dev culture just seems to have more give-a-shit about performance (and, relatedly, battery life) than anyone else's. See also: Safari, their office suite programs, Preview which is the first program I've seen that handles PDFs very well and doesn't also feel super-heavy (on the contrary, it's very light), Terminal which is more-or-less competitive input-latency-wise with the best available anywhere else and is way better than average, and so on.

While I’m not an ios dev, from what I gathered ios is just way more aggressive at telling background apps to save their state and then stopping them. This can sometimes be very frustrating (ishell basically being blank if one didn’t touch it for like 10 seconds), but is great for responsiveness, battery life and longevity.

Unfortunately this can be hardly retrofitted to other OSs since it requires cooperation from the apps.