Those efforts might finally have brought about the death of dynasties: It's been a decade since the New England Patriots won the 2003 and 2004 titles, the longest stretch without a repeat champion in nearly a half-century of Super Bowls.
"The days of the dominant teams may be gone forever," said Ted Sundquist, a former general manager of the Denver Broncos and their director of college scouting when they won back-to-back Super Bowls in the late 1990s. "It's hard. It's beyond hard. There are different types of players now, different types of systems set up. The game's changed."
Sundquist is among those who thinks the reigning champion Seattle Seahawks could be equipped to buck the recent trend. Their roster was the fifth-youngest in the league last season, according to STATS. They have plenty of stars on both sides of the ball, including quarterback Russell Wilson and cornerback Richard Sherman; and GM John Schneider and coach Pete Carroll set the tone.
"From a leadership perspective, John and Pete are not the kind of guys who will lose their focus - and I think that will trickle down to the players," Sundquist said. "What's really working against Seattle is that they're in a dadgum competitive division."
Joe Theismann, the quarterback on Washington Redskins teams that won the Super Bowl after the 1982 season and lost in the championship game a year later, also thinks Seattle is in a strong position.
"They have a lot of things going for them. Their stars are young. They play in a very tough place to compete for other people," Theismann said. "I would be extremely shocked to see what we've seen from other world champions. Baltimore, two years ago - so many guys retired, so many guys left, and now they're retooling a little bit. That's not happening in Seattle."
The Seahawks' fans certainly are holding onto last season, trotting out fake Lombardi Trophies to training camp practices. But Seahawks are not boasting about the franchise's first championship or talking about the route to No. 2.
From the moment the preparation for this season began, they were concentrating on the facets of the game that helped them rule the league a year ago, primarily the sure-handed offense and opportunistic defense that allowed Seattle to lead the NFL in turnover differential.
"When we came back in, there was no talk about repeating," receiver Doug Baldwin said. "It was (about) going back to the basics."
The Seahawks opened the preseason Thursday night with a penalty-filled 21-16 loss in a Super Bowl rematch against the Denver Broncos.
The history of the Super Bowl has often been very much about prolonged success, from the Packers' triumphs in the first two meetings between the champions of the AFL and NFL, to the repeats by the Dolphins, Steelers (twice), 49ers, Cowboys, Broncos and Patriots.
So what happened?
Teams are less deep nowadays. That makes health more important, because if a key player goes down, there tends to be a bigger drop-off. Keeping a roster intact is tougher, because players depart via free agency (Seattle lost receiver Golden Tate and defensive end Red Bryant, for example). Assistant coaches get hired away. Younger players might think they're under-appreciated and demand more money (Seahawks running back Marshawn Lynch initially held out). Older players might not have the same drive anymore.
The shorter offseason, Baldwin pointed out, means champs "don't have as much time to recover" physically or mentally. The instant-celebrity world and heightened media attention create more distractions.
Schedules get tougher for a winner - another element in the NFL's path toward parity - and, of course, everyone wants to try to beat the previous season's best.
"There's always the unknown. Injuries. Off-the-field and offseason situations. Contract holdouts. Kind of that 'fog of war,' I like to call it," Sundquist said. "It's like NASCAR: You can be flying along and all it takes is one cylinder to pop on you and you're not running at full efficiency."