Window 8 - Metro Style Apps, A big market to make money

I am seating here in (Fairmont PacificRim center) for windows 8 development training (Windows App development for phone, tablets, laptops) . Here I have got a interesting numbers for Windows OS which is a great opportunity to make money with windows app market.
You can make one app which will run on desktop, laptop, Tablet, smartphone.
Here is the number of devices for windows OS:
Windows OS - 500 Million devices
Android - 232 million devices
iPhone - 152 million devices
Mac OS - 30 million devices
If you think 0.01% pie of this Windows device than you can calculate the amount you can make with $0.99/App. With 01 app of $0.99, you can make 1/2 million dollars. This is not impossible :), so go for it.

So if you make an Windows app using windows 8 OS with Visual studio 2011, it is easy to make such apps and it is also easy to submit on Windows App store using Visual studio.
The only thing you need is one time registration fees with windows app store, which is $49.00 dollar - individual, and $99.00 for Business.