I know an importer who told me a story he claimed came direct from the seller:
This guy sold a product that was only available from overseas from one supplier and knew he was the only person selling it in the UK.
His modest stock was kept by you-know-who who also dealt with fuilfillment.
He was doing well, but then people were finding people couldn't get his product because it was 'out of stock'.
Turned out YKW's algorithms had detected his stock was selling well, so they undercut him - and fulfilled their orders from his stock while waiting for their own to arrive.
Of course when his stock was replenished, he couldn't sell it at a profit because YKW were undercutting him...