You are absolutely right, having a mentor isn't a criteria for success, you can become very successful without having a role model or any one you look up to. Achieving success is all about dedication and consistency to you goals and ambitions. As a matter of fact having a mentor without having a drive or prospect would take you no where. Some people are of the opinion that having a mentor isn't necessary and believing in yourself and working hard is the only thing that matters, it's not entirely correct but it actually makes a lot of sense.
trying in every goal that we want is also one of them, to achieve success even without assistance a mentor someone can be more advanced, the need for enthusiasm in oneself can also motivate to make it better, because enthusiasm can show strong determination, to achieve the progress that is dreamed of for the future.