The only good argument for manned spaceflight is the same argument we use to justify "summer vacation". There is no economic justification for flying to Rome and looking at a 2,000-year-old sports stadium or hiking a trail in the mountains. We do those things because we like doing those things.
As robots and AI get even better in the best century there will be even less reason to send people to space, except for tourism.
It's impossible to argue against tourism. It is what people like to do and they don't need a reason.
As robots and AI get even better in the best century there will be even less reason to send people to space, except for tourism.
I’m almost tempted to say that Zager and Evans were prophets, ala Nostradamus. What I’m saying if you were to turn what they wrote into a quote you would have a hard time convincing anyone, based on what you say here that they weren’t. So, I will go ahead and use it as a quote for emphasis: “
In the year 5555 Your arms are hanging limp at your sides Your legs got nothing to do Some machine's doing that for you”
That notwithstanding I believe you are ignoring the human need/want found in their sense of adventure. Sure, a thrill found due to curiosity can inspire some to first go out and seek confirmation of what they may already know: like yeah, the stadium is old, but wow to actually have been there. Or seeking relaxation in a vacation where in you hike in a mountain.
I think those two fall more into the category of doing something out of the ordinary when it comes to having a fulfilling personal life. Going out into the unknown even when you know that there are real/unexpected dangers that may need to be, overcome. That is outside of the thrill-seeking realm of the vacation.
The thing is that as a vacation destination anything beyond near earth thrill rides is a long way, away. Something that’s not likely to happen even within the confines of our solar system until humans can get there and back. So, they can tell their friends and family what a thrill their latest vacation/adventure was.