- right place at the right time (almost certainly a factor here)
- actually building and releasing something
- promoting it, letting the world know about him/it
These success stories are really nice, but it's important to recognize that it usually takes all three of these key elements to be successful.
Obviously if you don't do anything, you cannot get success. But if you do something, and the timing or market is wrong, you may not get much or any success. And if you do something but never make an effort to let the world know, then you may get a little growth but not real success.
We can't control the market timing so much, mainly because we can't accurately predict the future. With some research, maybe we can improve on this, but it's still no guarantee.
So, the best policy is to just stay in forward motion. Built a thing, promote it, and repeat. Maybe with 5 things in current operation, one of them catches.