Michigan has won 11 national championships in football, but only 1 since 1948 (and that was in 1997). The legendary coach Bo Schembechler won exactly ZERO national championships. What Michigan fans expect is to consistently win Big 10 conference championships and be one of the top teams in the country every year. Suffering home blow-out losses to schools like Utah and Minnesota is not in the equation.
By comparison, Ohio State recognizes 7 national championships but only 1 since 1970 (that being 2002), yet everybody pretty much still recognizes the Buckeyes as a national football powerhouse.