The thing is, your 30-35 hours at a cushy office job isn't just 30-35 hours of fungible time - it's a commitment to a lifestyle that revolves around office work. A lot of folks talk like a person who has a job has the same amount of freedom as someone without a job, just minus the time they spend in the office. That's part of it, but there's also the loss of spontaneity/flexibility/control.
If those are things you really prize, then it can be perfectly rational to optimize your life for the maximum number of years in which you have total control (i.e. you're not working). If that's what you want to do, then it makes perfect sense to work as much as humanly possible and save as much money as possible on any year in which you're working at all, since you're giving up that total control of your life whether you're working 20 hours or 80. Then, when you've got enough money, you get total control of your life for as many years as possible. Depending on what you value, it can be a totally reasonable optimization.