Just because someone could go pro doesn't mean they want to. I know a few people who have the ability to train professionally - one is undefeated for many many years in Arabian Western Pleasure and Side Saddle at Region 17 with a few national championship titles to go along with it. Rarely is she out of the top 5 regardless of division. But, she stays amatuer as she has no desire to make a living training other peoples horses. An amatuer is someone who does not make money from training, managing, breeding etc. It has nothing to do with skill level.