...
this CNN ( 
) article that tells us that
"The average iOS device owner will download 83 apps in 2011 [....]
..."82% of the apps in Apple's store are free. The 18% that users have to pay for have an ASP of $1.44..."By my math, that mean the average iOS device owner will spend (.18 x 83 x 1.44=) $21.51 on applications this year. If your friends were representative of Mac owners as a whole (not a point I'd cede without more scientific corroboration, but that's a different issue), then the $21.51 a year they'd have to average in Mac App Store purchases for that outlet to maintain the same revenue per user ratio as the [iOS] App Store doesn't seem to be much of a stretch.
Since the App Store infrastructure (iTunes, Apple ID/credit card database, developer revenue sharing model, etc.) is already in place, the startup cost to Apple of deploying the Mac App Store is pretty much just the cost of developing the Mac App Store application.
Let's not forget that the iPhone and iPod Touch sold extremely well
prior to the introduction of the App Store, which strongly suggests that the habit of purchasing iOS apps was acquired after folks already had meaningful relationships with their iOS devices. I suspect a similar dynamic is already underway with the Mac App Store.
