You are severely underestimating the effort that it takes to send people to Mars, unless you want them to expire there quickly. So yes, sending people to Mars really does compete with other efforts. Therefore we have to weigh the utility of such an undertaking against its benefits. It is true that sometimes “crazy” projects like this does reveal findings that you weren’t actively looking for. But that is the best argument for this crazy idea - that maybe it will turn up something unexpectedly cool! And I don’t see why we would divert a significant amount of resources to something like that when we have so many other fields that desperately need attention, where we know that we will find good and useful stuff without endangering the lives of people.

You mentioned soil research as one avenue for why going to Mars might help. Why do we need Mars to practice growing food without soil? What is it about Mars that provides a significant advantage for that type of research? None, you say? Then I say, let’s do it on Earth or in orbit.

I am also confused as why you keep referring to Earth’s moon as “Luna”. In my experience that’s mostly practiced when we’re comparing solar systems to each other, and in that context the Earth would be named “Tellus”. Although I think it’s rare to call them anything except “Earth” and “the Moon” in practice, at least it was when I did my physics degree.