The tickets selling in the $200-$300 ranges are people with tickets wanting to take advantage of the market and make some profit.
The tickets listed well above selling prices are people with tickets who want to, and have every intention, of attending the game, however would be willing to let someone else go for that price. They don't want to sell, but they will for enough dollars.
I have a can of Diet Coke Busch Light in front of me. I plan to drink it. I don't really want to sell it. But if someone offered me $100 for it, I will. Doesn't mean cans of Diet Coke are going for $100.