There are situations even worse - scammers first make themselves an excellent rating by trading themselves at a loss, and then they deceive a huge number of buyers.
Yes, I completely forgot about this option, although personally I came across this. I think the blockchain will help with protection from various kinds of unreliable sellers.
If the multi-signature function is added to the blockchain system, then in general this problem will be solved. The funds will be transferred only with the full satisfaction of the buyer.