Other cities are poor but their residents don't glory hunt elsewhere. Problem is we have 2 rugby clubs where glory in a smaller pool is easier to come by. In fact Hull rugby should have had more success when you look at the success places smaller than Scarborough have had in RL. A lot of people go to rugby and adopt another club, always the same few, to be involved in discussing the bigger sport at work and in tbe pub. They then actively wish their local football club to fail. A situation you don't get elsewhere, they either go to their local club, or don't, depending on success, finances etc. Used to go to rugby myself when City weren't playing. That stopped after the Brentford game.
As for poor, poverty was always given as a reason for fanatical support as a release from the everyday misery. The favella dwellers in Brazil, the poor in Naples, Glasgow and also the Liverpool of the 1960s. Things certainly have changed.