Shula was perfect in 72! But yes he did have some issues after that.
But saying he was largely the reason is Marino doesn't have a ring is way off base.
He put Marino in a situtation to win a ring and Marino had a horrible game in the Super Bowl in 1985
Then Marino followed it up with another stinker in the AFC Championship game vs NE in 1986
In 1991 Dan had another bad game this time against Buffalo and we were eliminated.
1993 home field advantage throughout the playoffs and Dan choked vs Buffalo once again.
I can go on an on.
While Dan was great during the regular season he had his own issues when the playoff came around.
In the 10 years that dan marino went to the playoffs every elimination game except one dan played a bad game.
In fact only once he had a good QB rating and that was the San diego game that he failed to score a point in the 2nd half.
The other 9 were all below par performances (77.6, 66.9, 54.9, 72.1, 56.5, 63.4, 29.3, 65.5, 34.6)
The ring was there for the taking and Dan just didn't deliver. Don't try to blame Don for that.
You've made my point for me. If Shula had ever drafted a competent running back and featured the running game more, he would have gotten the same results as Shanahan did for Elway.