It used to be one of the true glamour positions in all of American sports. Coveted and prized—its elite players enjoyed prestige, power, and respect. It commanded top-dollar and gave us the Heisman pose, for crying out loud! In the 1980s and 1990s, the Minnesota Vikings and the New Orleans Saints both paid a king’s ransom for just one of ’em (Herschel Walker and Ricky Williams respectively).

Ah… what used to be.

From 1955 to the dawn of the Salary Cap Era in 1995, running backs went first-overall in the NFL draft a whopping 14 times. Their names were legendary: Earl Campbell! OJ Simpson! Bo Jackson! (And the not-so-legendary: Ki-Jana Carter. Jim Grabowski. Tucker Frederickson.) They were the patron saints of the mainstream Football Gospel: Run the ball, control the clock, and win the game. Vince Lombardi explained his football faith when he addressed his new team, the 1-10-1 Green Bay Packers, prior to the start of the 1959 season: “Gentlemen, this is a football. Before we’re through, we’re gonna run it down everybody’s throats.”

And with power sweep after power sweep, Coach Lombardi guided the Packers to five NFL championships in seven years, becoming the iconic namesake of the Super Bowl trophy.

Then, in 1995, Emmitt Smith (one of six running backs selected in 1990’s first round) led the league in rushing while also leading the Dallas Cowboys to a Super Bowl victory over the Pittsburgh Steelers. Clearly, the RB position had cemented itself as the indispensable cornerstone of championship teams. For now and forever, the future belonged to running backs!

In the immortal words of the esteemed philosopher Yogi Berra, “The future ain’t what it used to be.”

In the 20 years since the Cowboys last won the Super Bowl, not a single running back has gone first overall in the NFL draft. In fact, since 2012, not a single running back has even been selected in the first round!

In the 1980s—a decade when first-round draft picks such as Walter Payton (fourth overall, 1975), Eric Dickerson (second overall, 1983), Tony Dorsett (second overall, 1977), Marcus Allen (10th overall, 1982) and Barry Sanders (third overall, 1989) ran roughshod—The New York Times published a survey of how much money NFL players earned by position. Running backs were the second-highest paid position, trailing only quarterbacks.

Fast forward to 2015: The NFL franchise tag for quarterbacks is the highest, checking in at $18.544 million annually. The next highest-paid position is defensive end, coming in at $14.813 million. Cornerback follows at $13.075 million. The next four positions, in order: linebacker, offensive lineman, wide receiver, and defensive tackle.

Running back is now eighth—ahead of just safeties, tight ends and punters/kickers.

Yes, the once-mighty RB has fallen from second to eighth on the NFL’s compensatory depth-chart. It’s a red necktie away from becoming the Rodney Dangerfield of pro sports positions.

In the 1980s, 54 running backs were selected in the first round. By the 1990s—the first decade of the salary cap—the number dropped to 34. And in the first five drafts of this decade, the number has plummeted to seven.

DeMarco Murray, the league’s reigning rushing champion, bucked the financial tide this offseason, jumping ship from the Dallas Cowboys to the Philadelphia Eagles in a blockbuster five-year, $42 million contract. But even though the Eagles are partying (and proportionally paying) like it’s 1999, the league has clearly changed: In 1995, when Murray’s old team last won the Super Bowl, the Cowboys ran the ball 50.05 percent of the time. (And that was despite fielding a first-ballot Hall of Fame quarterback in Troy Aikman and a Hall of Fame wide receiver in Michael Irvin.)

This year’s champions, the New England Patriots, passed the ball 58.17 percent of the time. Jonas Gray (an undrafted free agent, incidentally) led the Patriots in rushing with 412 yards, which trailed Emmitt Smith’s 1995 tally by a scant 1,361 yards.

The league is dimensionally different, and it’s dimensionally different by deliberate design: Defensive backs cannot grab and redirect receivers as they did in earlier generations, and referees protect of quarterbacks. Just grazing the quarterback’s helmet results in a 15-yard penalty! Unquestionably, these rule changes encourage teams to pass. But it’s more than just rules; it’s also the salary cap: Each position cannibalizes the next, and durability matters.

It’s not personal. It’s mathematics: You can’t slice a finite pie into infinite pieces, and if the piece crumbles before you can eat it, it’s not of much value.

Paradoxically, running backs need that pie the most, since the average career for running backs is 2.57 years.

It’s been calculated that a running back’s peak year is 26 and every year that follows is marked with a sharp, precipitous decrease in production. Since most running backs enter the draft between the age of 20 and 23—and are often locked into rookie contracts four-to-five years in duration—the contracts that follow are often retroactively rewarding past production, instead of accurately projecting future production. Case in point: In 2005, 28-year-old Shaun Alexander of the Seattle Seahawks rushed for 1,880 yards and 27 touchdowns, averaging 5.1 yards-per-carry. Seattle rewarded him with an eight-year, $62 million contract ($15.1 million guaranteed).

He never ran for 1,000 yards again.

After signing that mammoth contract, Alexander netted a pedestrian 896 yards, seven rushing touchdowns, and 3.6 yards-per-carry in 2006. The following season he rushed for 716 yards, four touchdowns and 3.5 yards-per-carry. He finished his career with the Washington Redskins in 2008: 24 yards, zero rushing touchdowns, and 2.2 yards-per-carry.

DeMarco Murray turns 28 in February.

Since 1990, the average age of the NFL single-season rushing leader is 25.28.

NFL rule-changes protect receivers running routes down the field and certainly help keep quarterbacks upright in the pocket, but it’s difficult to safeguard a running back whose job is to repeatedly pound the football through defenders—especially in a league in which the players are getting bigger, stronger, quicker, and faster. Murray was a workhorse in 2014, carrying the ball 392 times, far more than any other player. In the past 20 years, only five other running backs carried the ball more than 390 times in a single season, and each time it took a debilitating toll the following year: Larry Johnson did so in 2006. Then, in 2007, he averaged only 3.5 yards-per-carry. Eddie George did so six years earlier in 2000. Then, in 2001, he averaged only 3.0 yards-per-carry. Ricky Williams had 392 carries in 2003, and promptly retired from football in 2004 to “find himself” before returning again in 2005.

The 1998 NFL season was statistically remarkable: For the first time, two RBs—Terrell Davis of the Denver Broncos and Jamal Anderson of the Atlanta Falcons—both had 390+ attempts. Sadly, both players’ bodies completely broke-down the following season: Anderson finished the 1999 campaign with just 59 yards, averaging 3.1 yards-per-carry. Davis did slightly better with 211 yards and the same 3.1 yards-per-carry. Knee injuries did them in.

Running backs don’t just use their bodies; they use their bodies up.

The Dallas Cowboys gambled when they let their leading rusher leave in free agency, and the Philadelphia Eagles gamble by surrendering so much cap-space to a battle-hardened RB like DeMarco Murray. This season, Philly spends $18.56 million on the running back position. By contrast, the Patriots spend $4.9 million.

As gambles go, the smart money is not with the Eagles.

And, unfortunately for running backs, neither is recent history.