Success is more random than your suggesting. IMO, the goal is to take risks that are in your favor. The less you know the harder this becomes.
If your default alive then you should consider being somewhat conservative. But, if your default dead then you need to risk something because your already losing.
The randomness of luck only comes into play when you've done everything else right, it's one huge 'AND' gate with luck as one of the factors. If you mess up on one of the others you're still dead no matter how lucky you were.
So by improving the rest of the gate functions the importance of the luck element goes up because it may be at some point the only item between you and success and then if it swings your way you're suddenly doing very well.
See also: the myth of the overnight success. All that is is a ton of preparatory work and one opportunity properly seized.
If your default alive then you should consider being somewhat conservative. But, if your default dead then you need to risk something because your already losing.