Honestly this sounds like a knock-on effect of the US's constant erosion of the glue of community. Church attendance down, sport attendance down, theater attendance with friends down, it's all the same.

Social norms can change this -- the Netherlands has a very similar culture to the US, But one thing people asked me while I was doing my M.Sc. there was just, "what is your sport?" ... and I got asked it enough that I eventually got one, and then for a good period of time I managed to completely kick my obesity, until I moved back to the American Midwest.

The introvert/extrovert axis also plays a role in what sort of "sport" is right for you, of course, and many of your sophisticated friends still hit the gym or jog etc. -- those are just sports for introverts in my view.

Sport time is not, time that could have been better spent elsewhere. It's like how cleaning the sink isn't time that could have been better spent elsewhere -- if you don't have a clean sink, you'll pay the interest in terms of "ugh what's that smell [...] oh it was the standing water in this bowl" and "crap I don't have a clean glass, hm, I wonder if I can just buy compostable cups on Amazon so that I don't have that problem..." etc. So as an extrovert, I can go once a week to play soccer with friends in a small league, or, just hear me out, I can get lonely and then do what I do when I get lonely, which is pop on Physics Stack Exchange and answer physics questions so that I can feel Of Use. You pay the interest either way.

Chess-time also is no great loss for the world. The top-level world chess community is something we have numbers for -- 17k titled players, 2k grandmasters, 4k international masters beneath that. They are pursuing something that exactly fits the nerdy way that their brain works -- memorize openings out to 20 moves deep, obsessively study and re-study their failed games to understand why the computer thinks they lost and how they might make better mistakes in the future, and for them it HAS to be competitive and they HAVE to have that immediate feedback of trying a new idea in the same narrow niche of ideas that they became a super-expert-in, against another top player who can punish their new mistakes.

It's just not a set of transferable world-changing skills. It's like, my brother became single-mindedly obsessed with pool in High School. This persists even though he now runs a small company operating a strip mall. This was just his thing, he loves that there is no upper bound to how much control he can have over the cue and the balls, using the spins of each to control the layout, and precisely planning a course through a 9-ball break and setting himself up for a clean sweep through the game. There was no world in which some "world-changing create-the-future" lifestyle, would have felt as much of a glove fitting his hand to him, as this did. And it is no great loss for the world that he found the glove that fits his hand. It's not like the strip mall would have become an American retail empire rivaling Amazon, if only he had spent his nighttime hours working on the mall instead of on his life passion.

For comparison, probably most of the people in the bottom 10% performance bracket at Google are being told and pressured "you need to do more, more, more, you're gonna get fired if you keep those low numbers up" and at 180k employees, that amounts to 18k people that, unlike top chess players, probably _could_ flourish and do better in some smaller scrappier company, but because America doesn't have a social safety net to speak of, they feel like "well I got the dream 6-figure job, I better hold onto that until my knuckles are white because if I got fired, Bay Area rent and cost-of-living could bankrupt me in 3 months." And that's literally just one megatech company, not even talking about the world of people Graeber argues are doing "bullshit jobs" etc. etc.