It was my understanding that many Japanese second-hand recycle shops exist mainly as fronts for being a source for a tax write-off for a larger entity. Hence, this is why the prices for used goods are hardly less than the same exact product if buying it brand new, because the things on offer aren't really intended to ever sell much.

And noted by @freecia above, it is indeed a headache to unload trash in Japan, to the point that it can even be cheaper, faster, and more convenient to just pay someone to simply take it off your hands for a small fee. Yes, a lot of the junk on offer in those shops were either given to them for free, or the shop even received money to take it! It's pretty common in residential areas of any city to hear vans driving around blasting messages on loudspeakers saying that they are looking to take any unwanted crap you may have.

But back to the true purpose of those shops. Most Japanese people don't ever consider shopping there unless looking for a specific collectable, so most of the inventory sits there forever unsold. But the jacked-up value of those items when they are unable to sell can act as a type of loss on their accounts (even though it cost nothing to actually acquire), and this standing loss can balance out any profit taken elsewhere within the overall company, such that in the end they nullify each other and no income tax is ever paid on what is actually profitable.

But now with all the foreign tourists willing to buy anything, well sure, they'll take the sale on an overly inflated price, because PT Barnum was right about suckers.