On both my private page and the page I run for a charity, I'm now only listing BIN with immediate payment. No more auctions. I get higher prices at auction (and eBay gets higher fees), but it's simply not worth the aggravation.
revenue-wise it would surely make more financial sense for eBay to take the problem of non-paying bidders a little more seriously as not everybody the extra time or the inclination to deal with people who shouldn't be bidding in the first place
Judging by the cursory messages "Don't need it anymore" and "I changed my mind" (that's when you get a message at all) they slearly think this kind of nuisance is ok and know that there will be no effective repercussions.
With seller fees at 20%, sellers deserve better than this.