Most of us have heard the saying 'those who can't do teach'. It's often in the context of someone not wanting to learn from another person who isn't perceived to be at the 'top of the game' in the field or area that they're teaching.
The thing is, teaching in itself is a skill. Not everyone who can do it, not everyone wants to do it, and not everyone can teach well. I know some very accomplished people who are terrible teachers. They might be at the top of their game in their chosen field, but teaching simply isn't their thing.
When I first studied to be a music teacher I was teaching students who were far more talented and accomplished than me at their specific instrument, some even completing their AMUS level performance exams at 13 years of age. However I still had a huge amount I could teach them, and I did. I was able to add value that had an impact on their skills, knowledge, creativity and performance as well as a skill I highly value, critical thinking.
I have friends and clients who have competed in sport at an international level. Each of those people have coaches and trainers who teach and help them gain valuable seconds, height, speed, rotation, prevent injury or whatever the focus despite not racing or competing themselves. When I've supported athletes I would learn about it and translate what was relevant to their movement and conditioning practices. I didn't need to race a mountain bike at World Cup level, or be able to do massive ski jumps to be able to teach and support those clients.
When I'm learning something I want to be guided by someone who can break it down, present and communicate it to me in a way that I can compute, process and implement rather than someone who is simply great at it themselves. Teaching is a finely tuned skill that a good teacher is continually evolve to support their students or clients.
When I want to uplevel having the right teacher/mentor/coach makes the world of difference. Why reinvent the wheel when someone has already done that. I'd rather learn from someone and evolve it into my own. We can always learn or evolve in some way.