That's such a tired argument that has a lot of misconceptions. The Lions offensive line was pretty capable and had 2 outstanding players in Lomas Brown and Glover. Herman Moore was an excellent receiver. Their 2nd and 3rd receivers in Perriman and Morton were quite good too. The biggest difference was consistency at QB with Rodney Pete and Scott Mitchell. Though Scott had a pretty outstanding 1995. 4300 passing yards and 32 tds which was 2nd and 3rd in the league. Go find that kind of season from Aikman. He didn't need it because he had Emmitt.
No doubt the Cowboys were a better overall team, but we can't pretend Barry Sanders had no talent around him and every yard he got was inspite of that. They had talent, the Lions just never ascended and Barry wasn't a factor in 5 of the 6 playoff games he played.