I don't think this is really 100% Amazon's fault , although, yes, they could police who is selling what on their site a little better, but it is up to the user to report scams also. You just need to be careful and read fully the description and feedback of what you are looking to purchase, if something looks too good to be true ..... then it probably is.
My experience is, I have bought some quality merchandise off Amazon , but most everything I had gotten from China was crapolla, IMO , I don't even know why we let them do business in the U.S. , most everything they sell is a knock off of something else.