The 2x4 crack was directed more at autos and pumps, and not to say there aren't good ones at all. Most importantly the gun that fits you is the one you should use, I think everyone will agree there. For campfire discussion I'll make my case.
Popularity shouldn't be mistaken for superiority. Trap and skeet is a whole different ballgame IMO with the added weight and feel a positive and alot of predictability in the target. Where the SXS shines is the speed of bringing to bear from a field position (again subjective). THe sxs can be ordered to suit, and I agree the beavertails are not my deal. I believe the British got the lines down for a proper bird gun a long time ago and that principal is what I stick with- splinters and english stocks. One thing about OU guns in thsi country is I never understood why english stocks werent more popular, the upland style Citoris are my hands down favorite of the Brownings.
As far as why there arent more- I think it is mostly cost and skill. There seems to be alot more to a sxs manufacturing wise. If you go back farther in history you will find plenty of competition guns and far more sxs guns afield. What did in Parker, Elsie, and teh others was cost of maunfacturing.