I'm basing this solely on Apple's size and age, but I'm sure they have their own internal QA and usability process that I'm willing to bet is far more stringent than the App store approval process (and it probably has something in common with the app store approval process.
Yes, but if something slips by their QA team and they want to push a patch out, they don't have to wait a week. And if they want the new version of iWork to come out the second Steve Jobs takes the stage, they can make that happen.
The App Store takes a lot of things completely out of developers' control. In the end, Apple is still in total control with iWork on the App Store.
Apple recently released the Gallery app, and released a new version with an authentication bug fix the next day. It's pretty safe to say that they don't have to resubmit apps for approval.
