Mentors certainly play a leading role in providing guidelines, but you won't always find a mentor around to guide you. Those who have great goals and objectives in life will be established in life even without a mentor. However, one thing is that if someone goes down the wrong path in life, a mentor can bring them back from that path and motivate them to lead them in the right direction. However, if a parent can guide their child in the right direction, then that child does not need any mentor other than the parents.
They are like drivers who only direct so as not to make a wrong turn or step but their presence is also considered necessary but not a factor and mandatory. as far as I know there are other people who are also successful in implementation of course they have a strong vision and resilience to face failure and they do it independently. It all comes back to us how wise we are.
Of course there are some people who does not like seeking for opinion, instead they will prefer doing it independently without consulting anyone. sometimes they can also fail and take immediate correction, of course this is how will learn. probably when you do it two to three consecutive times then you become a professional, At this point you will very much proud of yourself for learning all alone.