I was lucky to met many such people in my life - I will just point a few such as Ricardo Franassovici of Absolute Sounds, Lew Johnson of Conrad Johnson or Peter McGrath of Wilson Audio - people with great expertise and ability to transmit audio messages. Talking with them freely at dinners or in social events were marks in my audio life.
But most of what I learned come from magazines, articles and books on the subject. These people showed me mainly new ways and new capabilities of stereo reproduction, that there are no boundaries in it, except our wish. And that for each door we open, we must close several others.
And I should not forget the influence of recording engineers, always intrinsic in their recordings.