I dredge up these stats occasionally, just to contrast the effect of TEAM on QB effectiveness. In Marino's 10 playoff losses, Miami gave up an average of ~210 yards rushing and ~34 points a game. 7 of those 10 games they gave up >200yards and >30points. Montana had 2 playoffs games where his team gave up >200yards rushing and >30points (both crushing losses). You basically can't win games against good teams giving up 200yds rushing and 30+points.
Montana's team gave up 16 points or less in 50% of his playoff games. ~33% of the time, they gave up 10 points or less. For Marino, it's ~19% (16 points or less) and ~10% (10 points or less). Those differences are pretty staggering, IMO.
This is the best summary of the issues with the Dolphin teams of that era that I have seen. It perfectly lays out what I have said all along about why Marino doesn't have a ring. It wasn't the lack of a running game. It was all about the defense. There are two names that sum up why Marino doesn't have a ring - Bill Arnsparger and Tom Olivadotti.
All of the Dolphins SuperBowl Appearances except the 1984 magically season were with Arnsparger as the DC. The Team's record and their defense with him was crazy. 9 out of 12 years they made the playoffs. In one of the seasons they missed the playoffs (1976), he came back in midseason. 10 of the 12 years they finished #1 or #2 in the division.
1983 12-4-0 1st -- AFC East 0-1 - Lost Divisional Playoffs Don Shula Roster / Stats
1982 7-2-0 T2nd -- AFC 3-1 - Lost Superbowl Don Shula Roster / Stats
1981 11-4-1 1st -- AFC East 0-1 - Lost Divisional Playoffs Don Shula Roster / Stats
1980 8-8-0 3rd -- AFC East -- Don Shula Roster / Stats
1979 10-6-0 1st -- AFC East 0-1 - Lost Divisional Playoffs Don Shula Roster / Stats
1978 11-5-0 2nd -- AFC East 0-1 - Lost Wild Card Playoffs Don Shula Roster / Stats
1977 10-4-0 2nd -- AFC East -- Don Shula Roster / Stats
1976 6-8-0 3rd -- AFC East -- Don Shula Roster / Stats
1973 12-2-0 1st -- AFC East 3-0 - Won Superbowl Don Shula Roster / Stats
1972 14-0-0 1st -- AFC East 3-0 - Won Superbowl Don Shula Roster / Stats
1971 10-3-1 1st -- AFC East 2-1 - Lost Superbowl Don Shula Roster / Stats
1970 10-4-0 2nd -- AFC East 0-1 - Lost Divisional Playoffs Don Shula Roster / Stats
IMO, if Arnsparger hadn't left the team in 1984, Marino would have his rings.