This is a problem even for macOS updates, ever since they moved to the sealed system volume in macOS 11. When you update macOS, it downloads the entire OS and installs it to a separate APFS snapshot. The infuriating thing about this is that the sealed system volume should actually make it easier to provide reliable delta updates, but instead they used it as an excuse to remove them.
And of course Apple's always treated app updates as "download entire new copy of app to separate container and relaunch", ever since day one of the iOS App Store. This too could be handled with APFS snapshots.
I really wish Apple - and the rest of the industry - would stop being so damned allergic to delta updates. It's infuriating knowing how much damned engineering effort, say, Google put into shipping deltas on Chrome, and then everyone else is "just download two copies of every app while you're updating them, bandwidth and storage is free if we don't pay for them".
I am pretty sure App Store updates are smarter than that. For example Xcode delta installs have taken far less space (though they take a lot longer) if you grab them from the App Store.
And of course Apple's always treated app updates as "download entire new copy of app to separate container and relaunch", ever since day one of the iOS App Store. This too could be handled with APFS snapshots.
I really wish Apple - and the rest of the industry - would stop being so damned allergic to delta updates. It's infuriating knowing how much damned engineering effort, say, Google put into shipping deltas on Chrome, and then everyone else is "just download two copies of every app while you're updating them, bandwidth and storage is free if we don't pay for them".