Once when I was at a poetry reading in Australia, a man came in singing “You have to believe in yourself… you don’t have a position because you don’t believe in yourself.”
That man didn’t know what he was talking about.
I have known a number of strong and successful people. Most of them did not believe in themselves, they believed in something greater than themselves. Probably the strongest person I know was my grandmother. She did not believe in herself. She believed in Communism.
I have known strong and successful Christians. They didn’t believe in themselves; they believed in Christ. I have known strong and successful businessmen and engineers. Many of them did not believe in themselves, they believed in Reagan conservatism and the American dream.
If you believe in something greater than yourself, then you are more likely to do difficult and dangerous things than if you believe only in yourself.
The aforementioned man is free to be as self-centered as he wants to be. He does not however have the right to force that attitude on others. Once a very intelligent and compassionate woman said that if she can’t live for herself she can’t live. This is ridiculous. There are many things to live for besides yourself. To claim that people not only should, but must, live for themselves is an outrage.
The truly obnoxious feature of these people is that, because some of them are successful, they think that they own success. This is completely wrong. There are all sorts of ways to success. There are successful Muslims as well, and I am sure that they credit Islam for their success just as much as these people credit believing in themselves. It doesn’t mean that I need to be a Muslim in order to be successful.
So I don’t own half of Melbourne and I don’t have a Rolls Royce. However I have made major contributions, translating a vast body of Russian poetry into English and having original thought on a range of subjects (https://sites.google.com/site/ilyashambatthought). I have a beautiful daughter who loves me, and I have many good friends and many people who respect me. My life is quite a nice one, and it is successful enough for my purposes.
So no, believing in yourself is not the only way to success. There are many ways to become successful. The person who believes in something greater than himself is more likely to do valuable things than a person who believes only in himself; and steering people in that direction stands to realize greater good than prevailing on people to believe in themselves.