IMHO being a "Pro" or an "Amateur" (Hate these words) is all about a matter of attitude and not if you "get paid" to sail.
If I recall correctly Laruffa won the Tiger Worlds ahead of the "Pros" by having a professional (thorough) preparation.
In Holland anywayz the "Pros" get beaten by the "amateurs" on a regular basis. If you dont have a professional attitude you will indeed always remain an "amateur".