We all have our reasons why we pay exuberant amounts of money for these rare and non-rare games alike, a topic much discussed before, many times.
Validation of purchase of these expensive carts comes from the fact that much of the time, if the game has not sold by vendors like ng.com, for many years, depreciation already happened. If you bought low, you could sell it for what you paid for it, more or less. Especially with AES games, buying these things is analogous to low-risk stock accounts. Look at MS3... I got uber lucky and was able to snatch a preowned copy for $180 off ebay last year. Now boom, the game is pulling what, $250 because of its relative rarity and demand?
MOTW is inarguably one of the best fighters ever designed. That fact only exacerbates its high value.