The speed and ease of developing apps in WP7

The video speaks for itself. The developer started working on his app at 3 pm and already has it up and running  just a few hours later, and at the same stage as a similar Android app that he has spent two weeks on! The demo proves how it is easy to code for WP7 (move over Android App inventor!) and with that in mind, I pose this question, are there still doubters out there who think that WP7 will not have a quantity of quality apps at launch?