I wouldn't be surprised if they wanted to force people to create native apps instead of allowing web app file uploading via the browser. Forces extra people to buy a developer license, so more money for Apple. And not to forget, more apps in the store...
Unlikely given that iPhone 1 launched with no SDK and Jobs claiming web apps were just as good. That it wasn't in that initial OS was bizarre enough - that it persisted until iOS6 is really odd.