Is it that rare? Yes.
Is it worth $3500? No game is worth $3500. $3500 will buy you a two or three year's supply of weed. Even if this game were REALLY fun, it wouldn't keep you high for two years. If you're not in to that sort of thing then substitute the weed for a good used jet ski, or a trip to Europe. The game can't be as good as a jet ski or a trip to Europe. Not even the best game ever (Yoshi's Island, btw) is as good as a two year weed ration/jet ski/trip to Europe.
Now, the question you should have asked:
"Is this the going rate for this game?" Probably.