you nailed it chris.
and a collector usually seeks to be educated by and seeks to educate others about the collectable. he found, at some point, nuances in a collectable that redifined his perception. he takes on, almost, the role of academia. it's a whole different level to be viscerally absorbed by the beauty of a collectable. that's not to say a dealer cannot assume any of the qualities i mentioned, but let's just say it's a different level of awareness.
and what art collector hasn't at some point sold any of his collection? yet given the finacial means, i think a collector will pay anything to round out his collection, but i don't know if any dealer is willing to go that far. and it's not to say that a dealer can't build his own personnal collection, and thereby qualify as a collectOR,,,,but will he travel that much further to understand the mindset of the artist?
it's all a very grey area, so i've arrived at a standard by which we can all use......if you sell more than 19.8763% of your collection, then you become a dealer.