It doesn't matter because they've already locked it down on the demand side. You can distribute iOS apps anyway you want, but people won't be able to install them.

Things are locked down on iOS but not (yet) on Mac OS X. My gut feeling is that this trend will continue.

For example, APIs are already being leveraged. You can only use iCloud if your Mac app is distributed through the App Store.

In the near future, Apple could switch Gatekeeper's default setting to Mac App Store only, raising another barrier to independent vendors.

Moving to a new processor would provide Apple a great opportunity to round up the laggards and force them into the App Store.