It’s a multiplication of x and y.
x is how much you are prepared, y is how lucky you are.
You are responsible for the x part of the equation, the y takes care of itself. If your preparation effort is zero, all the potential opportunities will be multiplied by zero and you will lose every one of them, no matter how big they were.
The more prepared you are, the more lucky you become. It’s not because you are lucky, rather because you can multiply small opportunities by big factors.
This idea is inspired by Richard W. Hamming’s thoughts on luck, mentioned in his book, The Art of Doing Science and Engineering. He walks through all the coincidences that led him to his discoveries. Those coincidences have occured for many people – none of them were prepared, only Hamming was.
Could you have discovered what Hamming did if you were in his position? Yes, only if you were prepared.