On the iPhone the competition is fucking insane and it depends on a lot more than just your product. First, yes, you need something that is amazing, better than Reflexion for sure, but you also need to have the connections to get it pushed at launch so you get in the top 25. Once there, if your app is brilliant, then you will make bank, no doubt about it. But there's a lot of if's there. You'll notice that the players doing well in the AppStore now (repeatedly) are the ones that can leverage previous hits to catapult new ones. To give you an idea of scale, the few days we were a top 25 game we were making over $1k a day.
On Android, the money just isn't there yet. The culture so far doesn't seem to encourage paid apps to the same extent as the iPhone. We've floated up and down in popularity in the Paid Applications section and have done ok, but nothing you can really base a business on. Somewhere around $3k/month I believe.
The figures in the article using 'average' are way way off. My experience, as well as what I've heard from others is that the 'average' paid app makes nothing at all. Perhaps if you are in the top 5% then you are making a little bit, but a pittance, and the top .1% is rolling in it. This is especially true in the iPhone store, divide by 100 for the Android store.
It's a tough way to make money, no two ways about it.