What a stupid comparison. Is it directly from Microsoft, trying to fool developers into thinking that writing software for WP7 is already more profitable than writing software for Android?
Anyone with at least tiny knowledge about mobile software markets knows that this is simply comparing apples and oranges.
First of all, there is practically no market for paid apps on Android. There are multiple reasons for this, the most obvious probably being that most people cannot even buy them. This is because on the official market you can still pay by credit card only. That probably works fine for the USA where every- but in Europe many if not most people don't even have a credit card, because nobody uses them over here. For example, there are three Android apps that I was really willing to buy - but I didn't, simpy because I don't have a credit card. I never used my last one, and I'm not going to get a new one only to be able to buy Android apps. If Google doesn't want my money, that's fine with me.
Ad-supported software has always been (and still is) the only way to make money on Android. Developers who sell two versions of their Android software (a free but ad-supported one and a paid but ad-free one) will earn way more money from the free version while the paid version will probably just get them a few bucks.
And another reason is of course that there is still hardly any software for WP7 available yet. As long as there are just a few games out there, each single one of them will get more attention than on Android where dozens of thousands of games are trying to catch the users attention.
So in the end the only good reason why developing for WP7 might become more profitable is because the same software on WP7 is usually several times as expensive than the Android version. While that is a slap in the face of the customers, it is indeed an advantage for the developers.