I bet we can all come up with examples of niche markets and sellers. For me, ice hockey equipment. Neither Amazon nor Costco can even come close to pricing and selection of the local chain store. Right down to a single puck. See how expensive one is on Amazon and not even official.
eBay can’t come close to sidelineswap on used equipment. $35 shipped with tax on a used $400 skate for a 11 yo. eBay maybe $130.
Why is the above the case? Imho expertise and free market.
I could see the tire scenario working if:
Prices half of the nearest competitor
All sales final
NO warranty, no exchange, no try and buy, no service before, during, after the sale.