The interesting question is, why do so many people value spending time ‘maximizing’ with uncertain prospects more than extra time to enjoy the trip?

I think people are different that way. When I visit a city on my own, I tend to just wander around and find a nice spot or meet some interesting people and do whatever flows from that. Whereas when I am with certain friends or family, there is always a schedule and a destination.

Well, travelling as a group of people almost always demands having a plan, otherwise “we’ll just wander around until we find something interesting” is a hard sell to get everyone on board.

Fair point. And that's why I prefer to travel alone or just with my fiancee. It's just much easier to, well, wander as you please.