New profession? My understanding was that we were discussing evolving our existing professional skills to stay relevant in the workforce.
But yeah, I think there are many books on spaced repetition and deliberate practice such that it's hardly a secret.
Besides, does everyone have a right to every single one of those things you've listed all the time? I wouldn't argue so, considering we're talking about people who are providing less value over time to their fellow human being.
When time conflicts exist, you must prioritize, and I would imagine "remain able to contribute meaningfully to society" (with caveats around capability) ends up being more important than, "maintain multiple hobbies".
And no, I don't think people are, generally, perfectly optimizing their time.