Well, I wonder if these will eventually become true collector's items.
Right now they're still common enough where they're not *that* rare. But as time goes on, they're disappearing (fires, people scrapping them, people hacking them up for bad MAME conversions, etc).
There's not as much demand for something like this now due to home consoles as well.
But in 10 or 20 years, will their value rise? Finding a Dragons Lair cab now for $500 is one thing, but how much will that same cab cost in the future?
Will it be something like a 1940s Wurlitzer Bubbler Jukebox that originally cost $800, but now costs $8000 due to how rare they've become? (And even though we have iPods which are cheaper and easier to find?)