CHARLOTTE, N.C. (AP) — Just a generation ago, NASCAR drivers raced until they were embarrassing themselves, the money ran out or they simply couldn't make it to the track anymore. They could compete into their mid-50s, and make a really good living.

It's an entirely different world now.

First went Jeff Gordon. Then Tony Stewart. Then Carl Edwards stunned everyone by walking away a month before the season began and just three months after he came heartbreakingly close to winning the championship. Now Dale Earnhardt Jr. is packing his bags to leave NASCAR .

All have their own reasons, but the nation's biggest auto racing series could be a victim of its own popularity. With millions on the table from sponsorships, prize money and merchandise, drivers can afford to walk away a decade earlier than the old days from a schedule that chews up 38 weeks a year.

The current crop of veterans — a group led by Matt Kenseth, who at 44 is the oldest full-time driver in the field — came up during NASCAR's big boom of the early 2000s. Breaking into the big leagues as part of the "Young Guns" push just about guaranteed a 20-year Cup career and a cool $50 million in earnings. Ryan Newman was part of the 2002 class with Jimmie Johnson, and combined they have run 1,107 races and earned more than $238 million in race winnings alone.

The entire industry was getting rich behind fat sponsorships and huge television deals, and the packed grandstands certainly helped. When Earnhardt announced Tuesday that he was retiring at the end of the year, Texas Motor Speedway President Eddie Gossage knew the immediate effect it would have on his gate.

"Dang it! Dale Jr. put my kids through college and I was hoping he would stick around long enough to send my grandkids to college," Gossage said.

The money made the last 20 years in NASCAR is just one reason drivers can walk away earlier than before without having to worry about their next meal. Brian Scott pulled the plug on his journeyman career at the end of last year to spend more time with his growing family. Greg Biffle would rather sit on the sidelines this year than take a ride with a low-end team. And Edwards? No one really understands his decision after he came 10 laps away from the title.

Gordon, with a bad back, had a chance to move into the television booth and spend more time with his kids. Stewart, physically and mentally drained after three years of upheaval, wanted his life to involve more than just NASCAR. Earnhardt wanted to be able to walk away when he wanted to, not when a doctor told him his next concussion would be one too many.

Earnhardt will turn 43 in October and he's a newlywed who is just now learning that two-week vacations in Hawaii are pretty sweet. Stewart earlier this year vacationed with his extended family for probably the first time in his professional career.

Earnhardt touched on the demands of the NASCAR schedule before the season, when he noted that he was doing nearly 90 sponsor or team commitments in addition to 38 races.

"Back in the '70s and '80s, when guys were racing into their 50s, they were running 28 races and had a lot of time off," Earnhardt told The Associated Press in February. "They didn't have sponsor responsibilities. Ninety days of work off the track? What was Bobby Allison doing in '83 with Miller? Twelve days off the track, maybe? They had a lot of time to do what they wanted to do to unplug and keep their battery charged."

He was asked about the schedule during his retirement announcement, but dismissed as hypothetical the idea that 10 fewer races might have led him to a different decision. He admitted he is jealous of the 33-race Xfinity Series schedule, but doesn't envision a scenario in which NASCAR can cut from the Cup calendar.

"Some of the drivers might want to cut a few races off the schedule, but I don't ever see that happening," he said. "We get out of the car for a couple months, the month of December and January, and we talk about, 'Man, that was a long season,'"

No matter how much money is in the bank, or how much free time they have on their hands, the call of the track remains. Gordon ran the 24 Hours of Daytona in January. Stewart has a packed sprint car schedule, spinning around on little dirt tracks far off the beaten path. Earnhardt plans to race in two Xfinity races next year.

"Any of those drivers, even though they're glad to be off, would love to strap in one and just go race somewhere," Earnhardt said. "It don't last long before that feeling that you need some time off. You're ready to get back at it. I think it's a part of the competition and the competitor inside you, but it's also because we're all a family."

___

More AP auto racing: http://racing.ap.org