And then it pisses people off (having to wait 6 months).
Which in turn hurts account creation, for sale area traffic, revenue from ad impressions (banners/search engine etc) and so on.
The no editing was done after much debate, and deemed to be the best solution.
Min post/signup requirements have little bearing on stopping people from bad trading.
Having their details, goods listed, prices etc - that works - we've proven that.