Very interesting. The trend in other arms for the past century has been toward detachable box magazines. Makes sense for shotguns too.
I still have some liking for the old shoot one, load one rigmarole of the tube fed shotgun, for in theory you never run out of ammunition. Nice theory, but the arrow of progress has been, lo these many years, to get away from handling individual rounds of ammunition in favor of the use of magazines, belts, clips, etc.