oh there are companies 3rd party that make a test bench software (that test all components). and if the repair falls into parameters considered acceptable, it passes. but these companies are licensed by specific manufacturer (rarely for example a company working for dell will do any work for hp) and closed lipped about the technology used.
I used to work for Samsung Intl. and we used such services for Laser Printers, Ink Jet printers and Laptops. collected RMA's stack on a pallet, shipped away, used returned refurbished in plain brown boxes, whe put back on shelf for a lower price.
refurbishing is very predominant in the cell phone industry. Newegg, fry's, and many other sellers used refurnished electronics. Phone carriers are the worst, after you buy your 1000$ iPhone x, say you break it, think they give you back a brand new one in exchange.. no. you get a refurbished unit.
as for amazon, they are not more in control of such things than any other reseller, nor will they ever will be, corporations like Samsung, IBM, Apple etc. are not going to take insight about how to run their business from a online sale shop. Amazon doesn't create, they just centralize shopping for the world, and sell TONS of refurbished products at higher prices than anyone else does. Amazon is a thief, I never use them for anything, because 99% of the time the competition be local or online are priced lower.