I asked myself this question because in almost every book or interview with successful people I come across a mention of them having, or even currently having a mentor who guides them, helps them develop, and perhaps points out mistakes that will not allow them to grow.
Life itself has taught one so much and with that not everyone you see successful have a mentor or any of that, some tend to grow by themselves and this is due to what they've seen in life and having a mentor seem like a control force to them but in the other hand some others see having a mentor as something useful, so I don't see anything wrong with it but it's not every successful person out there that have a mentor.