You do not need to have a mentor before you can become successful in life. There are many successful people in life that does jot have a mentor.
Some people only like after a role model and they may want to be like such people and work towards it.
But know that success is not about having a mentor or looking after someone as a role model. It is about how smart you are in achieving successes. Opportunity and exposure are also very important.
Likewise, people can also read books like Op alluded to both hard copy and online then build the kind of principle they want without necessarily going to one "godfather " ( what can also be called mentor) for some tutelage or direction about what to do in life and their finances.
Again, like you said, someone can build a moral character of success for his or herself by living a purposeful life, take their own adventural risk and survive afterwards. I have known of some stories of people climbing to higher echelon without support from people they know. What about the saying of destiny "helper " too? Destiny helper is not necessarily mentor but someone that can come in between the gap at a time of need and it may just be a random thing and one time thing. So, it is not always that people need mentors to be successful.