These guys (who I've worked with back when they were NHR) have massive warehouses of used equipment that you purchase for 70-80% off list. They sell about $250mm worth of equipment each year.

https://www.curvature.com

Here is their distribution center: https://www.curvature.com/DistributionCenter

Carrying inventory valued at $200mm.

You'd be surprised. There's a guy in San Jose with two giant warehouses full of Atari products.

http://www.bertelmann.org/atari-archive/be_en.htm