One club spent 15 years at the bottom of the ladder the other won several flags, no surprise solid support grew. I mean their supporter base knows a flag will come inside a decade.
Watch what happens when that starts to not occur
This is exactly the reason why the Saints & Bulldogs are on a slippery slope, they have a long history in the game but have bugger-all to show for it. Fans can't talk about being at the XYZ Grand Final when "we came home in the last quarter & pinched another flag".
The sort of things that entice people to follow a club are it's rich history, the ongoing infield success, the premiership glories etc etc etc.
Without that backbone, what else do you have to sell the club on to prospective fans ??
"Come and have a look at our huge cabinet of spoons ??" just isn't going to cut it these days.
Success breeds success ............. there is no other way around it I'm afraid.