What argument can be made for the Storm being the most successful team from 98-2006?
Broncos - 3 premierships, 2 minors
Roosters - 1 premiership, 3 runners-up, 1 minor
Storm - 1 premiership (1 runners-up, 1 minor withheld due to cheating)
If you take ladder positions into account for those years, Broncos are also ahead with 6 top four finishes, Roosters with 5 and Storm with 2 (1 withheld due to cheating).
I can't see anything that suggests that the Storm were the most successful team from 1998-2006, but I am interested to hear what arguments one could use to make this point.