This is something I've been thinking about for a while, why not make apps not require to be installed, and put them behind URLs?

Something similar to the way Blizzard does their games with the Battle.net client, e.g. you click "Install", and the game is playable after only a few megabytes, and then as you play things progressively load.

That could really disrupt the mobile scene, and Apple is well positioned to accomplish that.