A JavaScript runtime doesn't require a JIT to work, it just makes it a lot faster. That alone wouldn't keep alternative browsers from being in the store, there are plenty of reasons to want a different browser even if JavaScript runs slower on it.

Last I heard you couldn't ship any interpreted language on iOS, and this was the big reason given why you can't have your own browser (and many other types of apps that could benefit from some scripting interface).

But that's just one example anyway, and somewhat besides the point. I have no problem with Apple running their App Store and restricting what apps are allowed on it. I do have a problem with the App Store being the only trusted source for installing software and managing updates. It's one more link in the chain that makes any real competition on in the iPhone ecosystem beholden entirely to Apple's wishes.