Well, speaking about paddling, which is where I am most highly credentialed: Trained under several national team coaches, one of my former training partners won a gold in the Olympics, PSIA D-Team level in WW kayak, certified high-level instructor in virtually ever other discpline, guided on big, scary remote rivers in dark corners of the world (and on very, very choice US rivers).
I guess that I have been paddling / instructing / coaching at a high level now for 45 years? Maybe 5 years ago I unlocked what I thought was the last piece of essential information - the genesis piece that everyone needs to embrace to be better in that domain. But I still learn every day. And I suspcet that I will discover more genesis pieces as the years go by, or refine the existing ones.
With ski instruction I have been at it maybe 30 years. I have never had national team training in ski. Although I have sponsored various national teams, athletes, etc. and had access to their mentorship.
I guess for me it is more of a journey. You learn every day, if you keep your mind open. I know one industry veteran, in his 70's - former national team member, ran Vail ./ Beaver Creek Ski School for a decade +, contract product developer in skis and boots for 30+ years, and he continues to learn everyday. He moves like silk in the wind on skis. He is my muse.