When sellers get vast amounts of negative feedback and excessive numbers of cases opened against them, Ebay do act - sometimes by increasing sellers' fees and, in some cases, by closing accounts.
Buyers are protected by the Money Back Guarantee and should continue to open cases, return fake items, and leave negative feedback.
Buyers can help themselves as well by looking at feedback received by sellers and by considering that old adage 'you get what you pay for'.
Personally, I also check that sellers with large amounts of new clothes for sale are correctly registered as business sellers.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)