Here are some reasons I can come up with (3 is weak): 1) Fancy updaters with bindiff and compression take time and money. As a first step, you need repeatable

Here are some reasons I can come up with (3 is weak): 1) Fancy updaters with bindiff and compression take time and money. As a first step, you need repeatable builds. 2) A broken fancy updater results in a reinstall, support calls and refunds. 3) If the updates are pushed by the store, there is no incentive to reduce the cost. With those three, if you can get away with shipping everything that's changed, you're going to do it.