How come the 1977 Atlanta Falcons do not get the credit they deserve?

Partly because teams like Baltimore (speaking of Dilfer) have actually won the Superbowl with a great D and virtually no offense. The Falcons did have a great D that year, but 7 - 7 just isn't worth writing home about no matter how you got there any more than the teams with great offenses and virtually no D, like several editions of the Broncos. Unfortunately, team defenses or offensive lines rarely get remembered without winning, but individual skill positions do.