5. Georgia Frontierre being cheap toweard Eric Dickerson. In 1987 the Dick was upset about his contract(similiar to TO) with the Rams. Georgia got tired of it ordered him traded. He was traded to the Colts, with the unsigned Cornelious Bennett going to Buffalo. The next year the Rams draft Gaston Green istead of Thurman Thomas, leaving Thomas to get drafted by Buffalo. This entire scenario made Buffalo powerful, and the Colts good, and probably cost Marino led teams at least 3 division titles(1987, 1989, 1990).
4. Jimmy Johnson ruling out drafting Randy Moss in 1998. Moss was still availible at pick #19, the Dolphins pick. However Johnson was afraid of Moss's reputation and traded down twice, ending up drafting John Avery.
3. Extremely poor drafting in the 1984-1989 period. With the exception of John Offerdahl(2nd round 1988) and Louis Oliver(late 1st round 1989) every pick in the 1st 3 rounds those years were fragile stiffs(Lorenzo Hampton, Jay Brophy, Jackie Shipp, John Bosa, Eric Kummerow, Rick Graf, Sammy Smith) that greatly dragged down the team.
2. The Joe Robbie family. Robbie was cheap(Marino even had a nasty holdout in 1985), and often would not be willing to sink the money for needed help. Also he did not set up a good succession plan. So when he died in 1990, the estate was set by in-fight among the Robbie children. This also caused financial holdups that prevented needed help(like not getting Bernie Kosar in 1993, and not locking up Louis Oliver to a cap friendly deal) in close years.
1. The endless search for replacements for players that died. Three starters, linebacker Rusty Chambers in an auto accident in 1981, linebacker Larry Gordon from a cocaine induced heart attack in 1983, and tailback David Overstreet in a drunk car accident in 1984, had passed away leaving major holes at key posistions. The line backer spots were weak for Shula's final 13 years. Shula traded the rights to Anthony Carter for Robin Sendlien who was awful. A couple of picks were traded for Hugh Greene, who after blowing a knee in his 4th game was never great again. Draft picks Jay Brophy, Rick Graf, Jackie Shipp, and Audrey Beavers were disaters. As for replacing Overstreet, high draft picks Ike Hampton and Sammy Smith were collsal failures, and Bobby Humphries never showed the talent he displayed in Denver. The failure to fill those spots, along with neglect of other parts of the team, doomed Marion's chances of the Super Bowl ring.