I agree that good genes can help us in life with better physical, mental, and emotional attributes, and these attributes can positively affect our relationships, careers, and social lives. It's also seemingly unfair but true that being born and raised in a good environment versus a bad one generally offers one a better chance in life for economic success, peace, and prosperity. But, I don't believe that genes nor circumstances necessarily dictate our paths in life or determine our success or failure. Look at the many rich, famous, attractive, seemingly successful people in life, like Whitney Houston for one, that struggle through life to the point of eventual suicide. At the same time, you read, hear, and see the stories of poor, plain, simple folks leading a satisfying life of purpose and satisfaction. Clearly, there's something more important governing the success and happiness of our lives than the genes we're born with or the environmental circumstances we're raised in. For Americans at least, who generally aren't struggling daily with war, famine, disease, and life threatening hardships, and where the standard of living is better than 6000 years of generations behind us, I think one's success in life is determined significantly by the choices we make. No doubt, the many decisions we make in life affect our health, relationships, careers, and social circumstances, and these are all factors affecting the overall feeling of success or failure with our lives.
Just Games, your pondering of life at age 50 and assessment of whether you've been successful with it is a good thing. It shows maturity that many shallow people never acquire. However, I would not settle for the conclusion you've drawn - being only a survivor. While it may be too late to redo one's past career, relationships, or social affairs, that needn't prevent you from doing different and better in the future with the things that matter most in life. You've plenty of time yet, hopefully, to make your life count - to obtain some sense of purposeful meaning and success with it.
Of course there's many different definitions of what success in life is. And as someone who's enjoyed an extraordinary career, many good friends and relationships, and an adventurous outdoor life of fun, trips, and adventures, I won't deny that such blessings have given me much satisfaction and feelings of success in certain ways. But, I know now, as I get older and more mature myself, that many of these worldly experiences are not the measuring standard for success in life - certainly not the number of places I've been, sports and activities I've pursued, or career and finance goals I've achieved. As King Solomon said long ago, in the end these things don't matter. They're all pointless.
As a Christian, I know that we were all created for a purpose, and Jesus clearly tells us that the most important thing in life is to know and love the LORD, and the second is to love others. This is a life long affair to pursue and some discover the truth later than others. The critical thing though is to get on board, making this the center of one's life. Since our eternal souls are at stake by the choices we make in this short, temporary life, I'd suggest that the formula for success in this life is to be a Christian. That's the path that'll lead one best through this life AND to the next, better one that lies ahead.