To consider his career an underachievement would be insane, but I can't get over the fact Larry Bird's career was limited by a back injury that shouldn't have happened. Bird didn't injure his back playing basketball or working out - he was paving his mom's driveway during the offseason.
We talk about cryo chambers, custom made shoes and blood treatments in Germany as the comparative advantages of generations nowadays, but how about not doing hard manual labor - literal back-breaking stuff - and prolonging your career.
It's a part of Bird's mentality. He felt responsible for providing for all the Celtics employees, he knew winning means they get to earn a living, and he had the same attitude in his own life. Why pay someone to do the work I can do myself? He is just wired that way.
But, it's not like layers took care of their bodies as guys do in 2019. Smoking and alcohol were a lot more present then they are today, and apparently so was cake. During the Celtics 1990-91 season, sportswriter Jack McCallum detailed their aging and all that came with it (via Deadspin):
"I think I wanna be active," said Bird. "What I might do, though, is git in shape, git outta shape, then git in shape again. I won't do it like I used to, though. It's gittin' tougher. Three years ago I could lose fifteen pounds like nuthin'. Now? I don't know if I could." He had put on a few pounds when he was out of action, but he wasn't sure how many. "I was so bored, I'd sit around the house, drive my wife crazy, and eat and eat. In two and a half weeks I was off I ate ten gallons of ice cream and seven weddin' cakes. Why them? I ate weddin' cakes 'cause you knew they was gonna be good. I mean, who would [eff] up a weddin' cake?"
I would respectfully disagree with The Legend. Wedding cakes are rarely anything to write home about. I'm not a nutritionist or a physio, but I suspect putting on weight and eating sweets doesn't help with an injured back.
Might be wrong on that one, though. I'm not about wedding cakes.