It is very easy to fake trades here, and many scammers give themselves fake trust feedback. This is somewhat mitigated on eBay because it cost money to engage in a trade (you need to pay the eBay fees), although that is not to say that all eBay trades are legitimate.
Feedback buying and account buying/selling on eBay is actually quite common. On eBay the feedback number displayed next to your username is a total of your buying/selling feedback, so buying stuff increases it. So many sellers will list ebooks for sale for $0.01. Other sellers then buy $10 worth these ebooks to get 1,000 feedback or so to prop up their reputation. IMO the eBay feedback system does have some advantages over the system here but it wouldn't work here and it still has widespread manipulation and is favorable for sellers (for example eBay lets high trust high volume sellers delete a set number of feedback per year to remove fake feedback) .