The app economy works because it has a clear pricing signal. The HTML5 economy may dominate the free and possibly some of the fremium end of the spectrum but, because it doesn't have clear pricing feedback, the app economy will always dominate the high end of the market.

Prices are a gauge. You read pricing signals to see where the market is and you use them to make decisions about how to bring something new to the market. If you don't have a pricing signal, you have to guess. This makes investment in the market very inefficient. If you don't have investment, the market won't last. So prices are critical in closing the information loop allowing investment. That's why I'm a believer in the App Economy.

With thanks to Horace Dediu.