No way an original MM is worth $8k now. Maybe $5k in great shape. It's 15 YEARS old. You can have a new one for $3k more = no brainer.

Four big reasons come to mind:
1) Anger. If someone just paid $10-15k for a 15 year old machine that's now worth about $5k... Well, that'd be pretty upsetting to have flushed around $5-10k down the toilet.
2) Jealousy. If someone paid $10-15k for a machine people can now buy for $8k (or less for a non-LE), well, jealousy kicks in for some. "Why are THEY getting a great deal?!"
3) I ain't special no-mo syndrome. MM is a great game... a lot of the old guard around here got them for great prices. Now, the masses can have one at least as good as the old one = "I ain't special no-mo syndrome"
4) Slaughtering Sacred Cows. Other sacred cows are sure to fall... MB, AFM, CV. A lot of people paid a lot of money for those games. See #1-3 above.

Everyone else who doesn't own a sacred cow game? We're all THRILLED.