No offense, but this discussion is ridiculous.
Pinball machines are part of the free market. Supply and demand determines the price. You could also say that a machine is worth what people are willing to pay for it. Using Attack From Mars as an example, it sells for $8k+ now because MANY people, in relation to the number of AFMs available, are willing to pay that. No one is paying $8k+ for a Data East/Sega game. In your opinion, a DE/Sega title may be better than AFM. But the majority opinion says otherwise, and they're proving it with their wallets. To say that they are somehow wrong for their opinion doesn't reflect well on you.
For the record, I don't really care for Attack from Mars or X-Files. But that's just my opinion.
Oh, and the people saying that DE/Sega games are more reliable than B/W...what!? You think that may be because those B/W machines were played a heck of a lot more?