Just a reminder, lots of things in that article are simplified quite a bit for the sake of putting together a coherent argument. The app store, in our experience, has an AWFULLY long tail. But our games have also been pretty successful - I would say the more complete statement is that you will do 50% of your lifetime revenue in the first 2 months, but it will take at least a year or so to earn the other half. That's not insubstantial by any means, but it also means that that revenue isn't terribly useful for building your next project (this is again a simplification, as the situation changes when you have more than one app bringing in that stream, etc etc).

So yea, I didn't mean for it to sound quite so dramatic, like the app store doesn't have any tail at all, because that's not really true. But for getting a read on your product's success and earning some useful revenue for the next project, those first 2 months in my experience are key.