One of my pet peeves is this notion that dying regrets is some sort of yardstick for how to live your life. At any age, it's easy to look back and think "why didn't I just...", but life is complex, and actions have unintended consequences. Personally I subscribe to the "que sera sera" philosophy. Control is limited. Life is a rollercoaster, just strap in for the ride.
But I agree with my boss on this matter. If you have kids, I think you should scale down your operations, have a 9-5 and spend time nurturing mini-yous to the fullest potential.
Your view assumes that those with dying regrets lack much critical analysis. That they espouse these regrets without having critically considered the alternatives. That no one has said to them 'oh you had a comfortable life, quit complaining' or 'if you hadn't worked, you wouldn't have had such a comfortable retirement'.
I suspect they have been told this over and over. And I suspect that they have thought critically about those regrets.
I guess I'm concerned about your quick dismissal of their potential wisdom.
Investigation into the playing of imperfect information games has revealed that one way to get a Nash strategy is by: playing in proportion to regret, then taking that strategy space which will oscillate around the nash strategy and averaging it. If you play the average of that set of strategies you will play the nash strategy.
Meanwhile, if you look at the world's richest human, his financial situation is a direct result of a decision made on the basis of regret. He made the decision to found his company on the basis of thinking about what he would regret. So we can also find a focus on regret as a successful strategy in the case of an outlier success.
When you're in your youth working, you have no idea what this number is and better to be safe than sorry. If the amount of work you need to do to get through life with your target level of comfort were "solvable", then people would do it. But capitalism is a world of exponential growth, decay, and unpredictability.
When all financial advisors stop padding the hell out of their client's target retirement date just to be safe, then we can say this regret is solely on the conscience of the person on their deathbed.