> The reason people go from work to nothing on retirement is because work fills up the nearly all of the productive hours of a person's life. If it were to take, let's say 4 days, or six hours a day, people would be so bored, they would be making projects, business ventures, or volunteering.

I don't buy this construction of the workday where spending 50% of your awake hours at work leaves people so exhausted they can't do anything else with their lives, but if we changed that to 38% of their waking hours they'd be so bored that they be starting businesses and volunteering all over. That's not even consistent with your own experience of being exhausted halfway through the work day. Two extra hours per day isn't going to translate to launching a new business or volunteer effort.

You hinted at the real problem: Most people don't have the time management skills and motivation that they think they do. Remove a couple hours of work per week from most people's lives and those hours will get redistributed to mostly leisure time. Some of it more productive than other options (socializing with the community, working on hobbies).

Are you considering jobs that are extraordinarily demanding? What if you're an ER Doctor? Or an Air Traffic Controller? Or someone getting started in their career in their early 20s, when most of us possess the unique combination of a lack of life experience that would prevent exploitation and ambition? For these jobs, I can easily sympathize with the idea that after a workday they're too tired to develop personally. Moreover, it's a manager's job to sap every ounce of productivity out of a person. Modern technology increasingly makes this possible. Even seemingly mundane jobs like working in a call center can be so orchestrated that using the bathroom makes them fall behind. And productivity has done nothing but rise for decades!

I also don't see how your final paragraph really refutes rather than just restates their opinion. Hobbies produce projects and business ventures all the time. Someone also has to find some way or another to socialize with the community. Volunteering is a great way to do that.

Jobs that you want to do vs jobs that you have to do are entirely different levels of motivating and result in completely different energy levels for people.

If I have to do a job I hate for the rest of my life I would eternally be low energy. If I could do the thing I loved every day, the thing I truly wanted to do, I would get up excited every day and would have high energy throughout.

Having more free time, yes people would get bored. But the resulting things that they work on would be things that invigorate them.