How will one develop apps in such an environment?
Sounds like a lot of negatives for Apple and few positives. Makes more sense to make it difficult for common users to do the things they don't want them to do.
Let me make my point clearer: I was talking about the ability of downloading and installing apps freely from the internet. What I meant was a closed ecosystem where you can only use approved apps from the app store without the ability to install apps from third partys.
That does not mean that you can't use the terminal or XCode (if those are approved apps), or get a "developer license" to "unlock" your Mac.