I think that this theory applies to highly scalable markets combined with common-purpose products, such as a web app for a certain hobby (e.g., learning to play

I think that this theory applies to highly scalable markets combined with common-purpose products, such as a web app for a certain hobby (e.g., learning to play the guitar). An ad-supported Android app ought to have a userbase of 200.000 - 500.000 users to confidently reach 1000$ of montly revenue - in this case I would say it is highly unlikely that you will ever reach 100.000$ of monthly income (except you write Angry Birds, of course - but they built upon the success of the game on other platforms, a thing an army-of-one could not do within the required timespan). For this exact reason, I consider quitting Android development for the time being.