OK lets be real here. Canada and the U.S never had the Worlds best ice dance team before Vancouver, except for probably Bourne & Kraatz in 2003 in a weak transition year. Some had said since B&S. Well since B&S:
1985-1996: U.S teams were so far from being worthy of contenders this period it is too laughable to even contemplate someone considering them winning anything. I will make a small note of Roca & Sur who were underrated and should have been regularly in the top 10 in the World, and maybe eked into the top 5 (but not on the podium) at some point. They were a much better pro team than amateur though. Canada had Wilson & McCall in the late 80s who were a good team, and deserved their bronze medals, but were probably lucky too that the judges dont generally like sweeps so might well have held W&M up into 3rd place to keep the 3rd Soviet dance team Annenko & Stretenski off major podiums. Bourne & Kraatz emerged as a promising team in the mid 90s but werent fully matured yet, and IMO were majorly gifted the 96 bronze due to home ice.
1997-1998: IMO Punsalen & Swallow were excellent and could have easily been given a bronze at one of the major events this time. I think they were competitive with a still developing Anissina & Peizerat and Bourne & Kraatz, but not competitive with Gritschuk & Platov or Krylova & Ovsiannikov. Bourne & Kraatz meanwhile were exactly as they should have been. Bronze contenders. Many today even found they were overrated in their careers.
1999-2002: Peter & Naomi were a good team and somewhat underrated. However not a top 3 team, should have been a top 6 or 7 team for a few years. Bourne & Kraatz again where they belonged, as bronze contenders, they were clearly never as good as a matured Anissina & Peizerat, and about the same level as several others, and the real underrated team of this time was Drobiazko & Vanagas.
2003-2009: Well this was the Belbin & Agosto era in U.S dance. The first U.S team you could seriously consider and hope to win a major title. Blumberg & Seibert were good enough, but had no chance in their time as the competition was way too strong. IMO they did as well as they should have in the end. It was dissapointing they didnt win a big title but were not robbed of it by poor judging, but just didnt improve after 2005 the way people expected, and the vagarities of chances didnt go their way in the later years. Their big chance at a major title was the 2008 Worlds which they blew with a fall. There was a case for them being robbed of winning the 2009 World title, but Delobel & Schoenfelder would have easily won this year based on the season to date had they been able to compete, just as Domnina & Shabalin would have easily won in 2008 had they been healthy and able to compete. Navka & Kostomarov were better than them in the mid 2000s, and Denkova & Stavyski and Delobel & Schoenfelder many thought were better too but politiked down below B&A to keep them away from N&K. If anything in 2005 and 2006 Belbin & Agosto were overrated to win the medals they did.
Bourne & Kraatz capatilized on a number of teams retiring and also had their best programs ever in 2003 to deservedly win silver at the post Olympic Worlds of 02 and their long awaited World gold in 2003, then retired due to personal strife betwen them and age. Dubreuil & Lauzon never had the footwork, speed, or overall technical abilities (apart from lifts), and did well to win 2 World silvers based mostly on their very romantic style of skating and great programs those two years. Lost a chance of an Oly medal due to a horrible crash.
Still Bourne & Kraatz, Belbin & Agosto, and to a lesser extent Dubeuil & Lauzon represented an improvement in the level of NA dance teams caliber. This improvement has continued with V&M and D&W who are clearly another level up from these teams. That has coincided with a MASSIVE decline in Russian, ex Soviet, and European dancing, which is also a HUGE part of the NA dominance and success in dance now, even with their own vastly improved teams compared to the past. Anyone who does not see all those needs to take the blinders of.
BTW Blumberg & Seibert were often jobbed I agree, they deserved silver at the 83 Worlds, bronze at the 82 Worlds, screwed themselves with a fall in 81 which set the tone of the pecking order that quad, and were robbed of atleast a bronze but IMO even a silver at the 84 Games. However there was no hope of them actually WINNING a major title that era with Torvill & Dean dominating.