Jimmy Johnson Cowboys. Not even close, really. By the late 80s, they were bad. Putrid even: 3-13 in 1988, 1-15 in 1989. And there was no other team in the NFC (or the NFL, really) during the Montana era that was as dominant as the 1992-1996 Cowboys.
Young had the misfortune of his team hitting its peak years as the same time as that Cowboys superteam.