People will always find a way to minimize Kwans accomplishments..Essentially, figure skating comes down to the big wins: nationals, worlds and the Olympics. All of the in-betweens (Grand Prix events) are important but they're small beans in comparison.
Michelle dominated where it mattered. Saying she dominated at nationals might not seem like a big deal now but back then the US ladies field had some of the top skaters in the world so it wasn't like it was a cakewalk or anything; she had to fight and, as a result, she delivered some of the best performances of her career there.
Michelle finished 2nd to Slutskaya 3 years in a row at the GPF so it's fair to say that Irina was the dominant GPF skater. But Michelle was a smart skater who knew how to pace herself for the long haul. Winning the GPF would have been great but her focus was on the big events: nationals and worlds. She dominated at nationals for a decade (winning 9 out of 10 years, 1996-2005 ) and she dominated at worlds for 8 years (winning 5 of those 8 years, 1996-2003).
As anyone in sports will tell you "regular season" wins are great and all, but everyone's eye is on the big prize at the end of the season (The Superbowl, The Finals, The World Series, etc.) and that's the one that carries the most significance. The Gran Prix series is figure skating's "regular season"; Worlds is the main event...if you get my analogy.