no, actually. while it's desirable for your qb to be your top guy, i don't think it's as necessary as we'd be led to believe.
looking at the same 20 year span that i used as an example for running backs, the following qbs were the best players on a super bowl winner:
2009 - drew brees
2006 - peyton manning
2001 - tom brady (2004 - i'd say seymour was more elite that year with he and vinatieri being all-pro and brady was pro bowl; 2003 - seymour, law or harrison were all-pros, brady wasn't even pro bowl)
1999 - kurt warner (or faulk)
1996 - brett favre