I agree with your conclusion, but I think there’s a fair argument to say that an extra week of leisure in your 20s is worth more than an extra week of leisure in your 50s or 60s. That is even more true if you’re working 48 weeks/year in your 20s and zero weeks in your 60s.

I think it's insane to, for example, work at an office early in your 20s, to put a couple grand in your 401(k). Those 1-2 years, if spent exploring, could mean finding a happier and more thoughtful way to progress through the latter 70% of your life.

"getting hit for a bus" is a hyperbolic example meant to stand in for a catastrophic event. It really means you (or a family member like a parent, partner or child) has a major health event, for instance. Some things are random, some things tend to become more likely with age. Even just chronic pain or other health issues might make retirement less fun than travelling in your 20s (speaking as someone with chronic pain from surgical implants).

Besides health there's a lot of reasons why being certain about doing something now might be preferable to putting it off for 10+ years.