I’m guessing this is what Apple has in mind. If not, this is at least what I think is likely to happen:
Actually, the scale’s off.
This is the much more likely outcome:
One of the reasons the iOS App Store is so successful is that app-buying has become a form of casual, routine entertainment for iPhone and iPad owners. We gladly go and browse the App Store even when we don’t “need” anything at the moment, with the intention of going and spending a few bucks on whatever’s new that looks good.
This requires a few conditions to be ideal, all of which are true on the iOS App Store:
There must be a large number of new apps being regularly added, and they must be easy to find and browse.
Apps must be low-risk. That means:
Trustworthy that they won’t do anything creepy or destructive.
Easy and quick to purchase and install.
Easy and quick to delete.
Enough apps should be good that people will remember the good ones and forget the bad.
In other words, a lot like iPad-app pricing, but shifted slightly higher. And even considering the lower prices than current Mac software, and Apple’s 30% cut, the value in exposure will overcome those for most good apps, and developers will be able to make a lot of money.