It's phase one of the passing fad that is game collecting. Those that came aboard several years ago, are starting to feel burnt out. People who started because it looked like something fresh and exciting to do back in 2007. The quickest to burn out are those who have lots of income to burn on it, and who acquire too much too fast. At first, it's just a few games, then it's "cutting out all the games I won't play anymore", then it's "getting rid of all but the favorites", and eventually they go too.
I know that in the six years that have passed, I've changed my own outlook on it several times over. I've given up several ambitions, and glad I did. It may be the hoarder in me, but if I grow tired of this all one day, I'm buying some tubs, filling them, and storing it all in the attic until I feel like pulling it back out again. Never selling. Not worth it, money comes and goes but this stuff is just a PITA to get (for most of us).