They weren't big enough to overcome voting collusion in the coaches poll (that is, if you were talking about #4 Cal before the bowls - stuck in a game traditionally reserved for the WAC champion).
The traditional Big-4 were all January 1 before the BCS (with the exception of Sundays in the case of the Rose Bowl). The Fiesta Bowl has become a major bowl, the Cotton Bowl has lost some if its former luster. The rest are pretenders.