I bought full sets of topps cards from 1988-1992 thinking they'd be valuable in 20 years, was I wrong. Effectively anything printed after about 1980 barely has the original value of the card (maybe even 1/3). I think I sold the sets, the other various Sox cards from the early 80's, I looked up the value of each (which was pennies) and decided it wasn't even worth attempting to sell, so I tossed them.

I'm not sure you can completely compare the comic book or sports cards to pinball. One is simply printed material, somewhat easily reproduce able. Then you have pinball. Yes it can be reproduced, but you are talking hundreds of man hours to reproduce playfield art, hundreds of hours to reproduce backglass art, hundreds of hours and lots of capital to reproduce any plastics or metal ramps. The $8k MM might be pre-designed, but I think it's still a lot of work to recreate it depending on how much data was saved before williams pinball division closed down. Planetary pinball might have the rights, but you just don't know how much work they had to do.