a number of those cabs were saved, stuff that was "safe" inside the barn. some of the cabs outside were scavenged for parts. but a lot if not most of 'em ended up being scrapped.
remember, these probably belonged to an operator who didn't care about them once they stopped producing revenue. proper storage is expensive, and why spend money to store 'em if they ain't gonna make any more money? disposal is also expensive so why take 'me to a landfill if you have a handy old barn?
a lot of operators did not like to sell their games because they were worried that the buyer might end up being the competition. Chuck E. Cheese was famous for that, throwing complete working games in the dumpster to make sure nobody else could use 'em.