Dunno how gamestop’s logistics works but they could leverage the existing shops as dropoff points for sellers and offer a pickup point option to bypass the postal system. eBay sellers are at a disadvantage vs Amazon warehouse sellers when it comes to shipping costs.

At least my shipping broker in Canada uses small retail stores as dropoff points and then has a network of gig courier delivery companies they send stuff to for last mile delivery. Saves a lot on shipping costs.

I’ve noticed they don’t really integrate with gig couriers for last mile US shipments, just a few consolidators for mid-mile (eg: UPS Mail Innovations that uses USPS for last mile)

Might further delay delivery times but I use eBay to save some dollars in exchange for delayed gratification.