If this is the way it is on the ultra-successful iPhone, can you imagine what it is/will be on other platforms?

Full Analysis of iPhone Economics – it is bad news. And then it gets worse

[...]1.43 Billion dollars divided among 164,000 actual paid apps gives the average app the revenue of $8,700. After Apple takes its 30% or $2,600 we are left with $6,100. That was over a two year period, so an average paid iPhone app earned six grand to its developers, ie in one year, they earned $3,050. This is the average, remember, it is not the median. The average skews too high because of the long tail.
[...]
Supercollider Blog reports on several levels of paid app downloads, the relevant number is that half of all paid iPhone apps get less than 1,000 downloads. The median point is under 1,000. Lets call it 999. That number times $1.95 per paid app gives the ‘most typical app’ the total revenues in its lifetime – the full two years of App Store existence – of $1,948 dollars. This is before Apple takes its cut of 30%, so we are left with $1,363 over two years or $682 per year. This is so ‘successful’ that half of all of the developers of the 164,250 apps – will actually earn LESS THAN THIS. Before you start to cry, remember, there is that Angry Bird game that had 4 million paid downloads and the Bewelled 2 game with 3 million paid downloads. Thats your math there, they are totally skewing the averages, and you are stuck in the ‘long tail’ indeed. Half of all developers will earn less than $682 per year. Do you still think this is a good business idea?

And at this point he’s not done yet. Yup, it gets worse as he looks at the cost of developing apps. He then does go into how to make real money (billions) from mobile apps.