After taking a sociology exam, Cardale Jones, a quarterback at Ohio State, posted a message on Twitter that echoed across college sports: “Why should we have to go to class if we came here to play FOOTBALL, we ain’t come to play SCHOOL, classes are POINTLESS.”

Two years after publishing that provocative statement, Jones will be the starting quarterback tonight against Alabama in the Sugar Bowl, the second semifinal game of the College Football Playoff, and his words have renewed relevance. Never has the sport been so awash in money, a growth industry on campuses that some observers believe increasingly resembles pro football more than higher education.

In some ways, even the NFL, that $10 billion-a-year enterprise, might be struggling to compete. Michigan on Tuesday introduced its new football coach, Jim Harbaugh, who left the NFL’s San Francisco 49ers to join the Wolverines. His base salary — $5 million annually for seven years, with 10 percent increases after the third and fifth years — will eventually amount to more than what he was earning in the NFL.

Harbaugh will have one of the highest base salaries in the country. The highest-paid college football coach at around $7 million this season was Alabama’s Nick Saban, who also chose to leave a head coaching position in the NFL, in 2007, for the riches of the college ranks.

“When you hear presidents and athletic directors talk about character and academics and integrity, none of that really matters,” said Mack Brown, a longtime coach at Texas who is now a television analyst. “The truth is, nobody has ever been fired for those things. They get fired for losing.”

Harbaugh, like most college football coaches, will receive bonuses. His incentives come for reaching the Big Ten championship game ($125,000), winning the Big Ten championship ($250,000), reaching a College Football Playoff bowl ($200,000), playing in the four-team national championship playoff ($300,000) and achieving team academic performance (up to $150,000). Winning a national title would bring him $500,000.

The story of college football’s gold rush can be told through television contracts. Under the championship playoff format that began this season, ESPN is paying $7.3 billion over 12 years to telecast seven games a year — four major bowl games, two semifinal bowl games and the national championship game.

Each of the five major conferences — the Southeastern, the Atlantic Coast, the Pac-12, the Big 12 and the Big Ten — will see its base revenue increase to about $50 million, from about $28 million under last season’s system. The base revenue will nearly triple for the five conferences that make up the next tier of college football.

The playoff is such a profitable showpiece that many believe it will be expanded to eight teams or more.

There may be an irresistible financial incentive to expand the playoff, but critics worry that such a move would further compromise the athletes’ academic obligations. Alabama’s semester begins Jan. 7; Ohio State’s starts Jan. 12, the day of the title game. The extra games could also prove physically trying to college players. The two teams that reach this season’s final will have played a total of 15 games.

“We talk about that in our meetings,” Doug Calland, Ohio State’s head athletics trainer, said about whether further expansion would be too much. “And I think it is. I think they’re pushing the envelope on how many — this is a long season.”

College sports have been growing more lucrative for years — ever since a 1984 Supreme Court decision effectively transferred power over football from the NCAA to the conferences and institutions, which led to television deals and even entire cable networks.

Including donations and other revenue sources, football brings in at least 65 percent of total revenue at major athletic programs, according to federal Education Department numbers calculated for The New York Times by OSKR, an economic consulting firm.

“In the old days, there was a much more even distribution of revenue between football and basketball,” said Lou Anna Simon, the president of Michigan State, who serves on the NCAA’s board of directors for Division I universities. “That has become skewed because of the value the public has placed on football.”

Mike Tranghese, the former commissioner of the Big East Conference, watched his former conference implode in recent years as it struggled to sustain a formidable group of football programs. Several member universities ultimately decided to retreat and emphasize basketball.

“I love the sport of football,” Tranghese said. “But the collegiate athletic world as we know it is absolutely controlled by the sport of football.”

Football is the main reason top-tier college programs have increased their revenue over recent decades at a rate that would make blue-chip companies blush. In constant dollars, the median Division I athletic department revenue in 1970 was $6.5 million, and in 2012, it was $56 million, according to one NCAA-commissioned study.

And nearly every Power Five program makes far more money than that figure. According to USA Today’s college financial database, Arizona State in 2013 had $65 million in revenue, Florida State $91 million, and Texas, one of the most marketable athletic departments in the country, made $165 million — 66 percent from football.

“Anytime anyone has tried to make the argument that college football is oversaturated, or there is too much, it seems to me, it ends up being a dynamic that it’s the more the merrier,” said Ilan Ben-Hanan, ESPN’s vice president for college football programming. “Fans pretty much have an insatiable appetite for college football.”