Enviroment, luck and means are as important as genetics imo. If you were born into poverty in some 3rd world country and forced to work like a dog your entire life, how would you know what your potential could be? If you never have to worry about money or material goods, you have a huge advantage over everyone else because you can spend your whole life doing what suits you. Luck trumps almost everything and can't be explained scientifically.
Genetics definetly matter, but I would say enviroment is probably 50%, genetics is 25% and 25% is shit that nobody can explain-- luck, chance, whatever you want to call it.