Put regulations on the Market Places to tighten up their process for accepting new sellers, and direct punishment of the Market Places themselves for selling bad products. These Market Places have no skin in the game when it comes to the stuff they sell, they need a reason to care. If they care, these problems start to sort themselves out.

For example, instead of just fining the AirBNB host for an illegal rental, they should also fine AirBNB say $50k per rental. Something high enough that they do their own verification of product. Or fine Amazon a similar amount every time they send out a fake SD card.