Grogan underachieved, Larry. Look at the talent on the Pats back then. O-line of Gray, Hannah, Lenkaitis, Sam Adams and Jordan. Stanley Morgan, "All World" Francis, Sam Cunningham. Sugar Bear Hamilton, Julius Adams, Tony McGee, Steve Nelson, Mike Haynes, Clayborn, Fox on defense. They should have had 2 or 3 SBs in the late 70s. The last game I saw in person at Foxboro was the 78 play-off against Bum Phillip's Oilers. Grogan had a miserable second half. That was a game they should have won by 3 touchdowns. Regardsless of the fiasco around Chuckles Fairbanks. HOF QBs don't lose their starting roles to the likes of Champagne Tony Eason
Every NFL coach back then also knew Grogan's glaring weakness--he never looked beyond his primary reciever on any play.