That's like saying people can fly by flapping their arms because birds can.

Auction houses store items for a limited period of time before liquidating them. The time in storage is fixed and the fees are fairly high. It's a fundamentally different approach to an online retailer.

An auction house that has to store items for years, charge no more than a 10% fee and only charge it if an item sold would go bankrupt.

Sure. So don't antique shops, but your customers do discovery and retrieval on their own, and the scale is orders of magnitude smaller. Auction houses can organize things into collections that are mostly accessed and cleared out all at once-- there's no random access to individual pieces in a giant churning collection, and they don't keep things around that don't get sold in case someone wants them. People can't get a single item from any collection auctioned whenever they want. It's the same problem space-- like going grocery shopping and sourcing food for a large hotel-- but to calculate the logistic viability of nearly anything in one task based on the other just doesn't make sense.