Maybe we should have seen it coming when Nick Saban, the greatest college football coach who ever lived, bought a $17.5 million mansion in Florida last spring.

Or when he finally took that delayed 50th anniversary vacation in Italy and not only realized the world wasn’t going to end, but that he was capable of having a good time despite being thousands of miles and several time zones away from his office.

Or when he jogged a victory lap around Bryant-Denny Stadium this October, waving to fans after Alabama beat Tennessee.

All along, the signs were hidden in plain sight. Saban, at age 72 and understanding how rapidly college athletics were changing, finally had enough.

Congratulations to him on a job more than well-done. Pity the rest of us who will never see his kind again.

There is an entire generation of young people old enough to drive cars who have never lived in a world without Saban churning out championships. They can’t conceive what college football was like as Alabama yawed aimlessly and embarrassingly from Dennis Franchione to Mike Price to Mike Shula. They will never be able to appreciate just how remarkable it was for Saban to figure it all out and build a Death Star like nobody had ever seen, within the span of a couple of years.

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When then-Alabama athletics director Mal Moore convinced Saban to leave the Miami Dolphins and come back to college football, there was no doubt he was going to win. But the way he did it — efficiently, ruthlessly and with the notoriously fractious Alabama boosters all falling in line — was a revelation.

And that was just the beginning.

He didn’t merely win football games, he changed the entire paradigm of the university. During Saban’s tenure, the school's enrollment doubled, its endowment exploded and more than half of its freshmen now come from out of state.

His innovations and search for every conceivable advantage forced the SEC to adapt or get run over, which it mostly did anyway. The old-guard coaches like Steve Spurrier sneered at pouring millions of dollars into fancy facilities and armies of analysts, but once Saban started winning, the competition had no choice but to try and copy his blueprint.

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Eventually, everyone who could was trying to recruit like Saban, spend on football like Saban and pay coaching salaries like Saban. Just like PGA Tour golfers owe their private jets to Tiger Woods, an entire industry owes generational wealth to a man who never wanted to coach until Don James talked him into it back at Kent State.

And then, when the game evolved beyond the so-called “murderball” style that won Saban his first three championships, he turned around and embraced the spread offense and won three more.

Whatever it was — name, image and likeness, transfer portal, the creation of the College Football Playoff — Saban adapted and won. He was always thinking, always pushing, always innovating to create an edge. When COVID-19 hit and football stopped, his first impulse was to get Apple Watches sent to the players so that their individual workouts could be monitored.

Alabama cruised to the national title later that year.

“I think it was because of the way we managed all the challenges that COVID created,” Saban said just days ago, prior to the Rose Bowl. “That kind of made me realize, wow, when something comes up, you better be one step ahead of the problem so you can adapt to those situations.”

His brain just worked differently, but he never lost sight of the most important factor in his success. Being the best football mind wasn’t worth much if you didn’t have the players. So when Saban got to Alabama, he recruited and recruited and recruited some more. By his third year, he made sure he never had to coach a game with inferior talent.

There will be plenty of talk in the coming days about whether all of the changes in college sports — more in the last three years than in the previous 50, he said in one of his final press conferences — chased Saban into retirement. While these developments had an obvious impact on college football, spreading out the talent and eroding Alabama's advantages to some degree, there was little doubt Saban could have won at the highest level for several more years.

If anyone thought the game was passing him by, the coaching job he did to get his final team to the College Football Playoff with a sub-standard offensive line and an erratic quarterback was one for the ages. All you needed to see was how Alabama played its best game of the season against unbeaten Georgia in the SEC championship to understand that Saban was still on top of his game.

The question now becomes what happens at Alabama. It’s not going to be the same. Pity whomever follows him — well, as much as someone can be pitied for taking an $8-million-per-year job.

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Athletics director Greg Byrne now must execute the most pressure-packed coaching search in the history of college athletics. There’s no natural successor, no in-house candidate and many viable options who simply do not want the responsibility of following a guy who went 199-23 over the last 16 seasons.

It seems unlikely Alabama could lure Kirby Smart away from Georgia, his alma mater where he’s won two national championships himself.

Clemson’s Dabo Swinney, a former Alabama receiver who has an out clause in his contract specific to this job, seemed like a natural successor after his two titles in 2016 and 2018. But Swinney’s struggles to adapt to the NIL/transfer-portal world, combined with his notoriously thin skin, might make for a toxic homecoming.

Lane Kiffin, who has turned Ole Miss into a consistently good program, has the personality chops to handle the Alabama fan base but does not have a history of winning high-leverage games.

Dan Lanning was an assistant at Alabama and Georgia before taking over Oregon, but he’s just 37 years old with two seasons of head-coaching experience. It's a risk.

Kalen DeBoer is coming off a run to the national title game at Washington and is clearly one of the game’s top offensive minds, but there would be a major question mark about whether a guy who was Indiana’s offensive coordinator a mere four years ago would be comfortable swimming in the shark-infested waters of the SEC.

There are no easy answers. And even if the Alabama fan base gives the new guy a grace period, it won’t take long before national titles are expected. That was true even before Saban. Just ask Bill Curry, who allegedly got a brick thrown through his office window after losing to Ole Miss in 1988 and was summarily run out of town after winning the SEC title in 1989 because he was 0-3 against Auburn.

Quite simply, whomever steps into that office next will have the toughest job in the history of college football.

But this was always going to be how it would go at the end, something the university and its fan base have been dreading for years. He couldn’t go on forever. Given all the factors, this was as sensible a time as any to stop.

If there’s one regret, it will be Saban’s final game. Alabama almost had Michigan beat on Jan. 1, needing to stop just one fourth-down play at the end of the Rose Bowl to have yet another shot at a championship. The Crimson Tide couldn’t do it — an incredibly cruel and un-Saban-like way to end a season and ultimately his career.

After his press conference, Saban hopped on a golf cart and headed back toward the Alabama locker room. On the way, he passed a group of reporters waiting to talk to the winning team. Saban gave us a little smile and a wave. We didn’t know it was goodbye.

This article originally appeared on USA TODAY: Alabama's Nick Saban could have won at highest level many more years