Just a question and i am going to be honest i am asking this questions because yes, i do want to be rich who woudn't?

What would be the chances of making a 2D game application for all mobile devices such as iOS, Android, Windows, etc and becoming a multi-millionaire, somewhere around the lines of Angry Birds and Candy Crush Saga and Flappy Bird.

And does anyone know how Flappy Bird got known and famous? Was it really luck that the programmer had? Did .. he do something else something i don't know?

when it comes to mobile apps like those, it really is all luck..

It's pretty much all luck, however there has been some studies done and the general functionality is as follows:

1. Simple enough rules to be instantly picked up and understood
2. Instant gratification with on-screen visuals of success
3. Designed around the idea of being played in short spurts rather than for long periods of time
4. micro-transactions that will help speed up point-gaining
5. randomly make things get incredibly harder to incentivize micro-transactions
6. Make free
7. Ads should not appear initially, but can appear after x amount of time or on pause screens, etc.