Re: Why barbless?
I believe it is a demand market. Although some fly fishermen may prefer barbless hooks the manufactures are probably looking at the broader market for hook manufacturing and sales. I would expect that until such time that there were a well organized boycott of all barbed hook sales there will be no sweeping changes to the hook selection at the local shops.
On another note, for dry fly fishing I do either buy or make barbless hooks but not always. To me the advantage of a barbless hook has always been to reduce mortality on those fish that manage to get hooked all the way back at the gill raker's. I almost always left the barb on my streamers, I'm not sure why.