I think you mean the benefit of technological advances from a mars trip.

A mars trip itself is only for those going. Most people don't get a part of it unlike pizza which can be divided

So, how would you define “taking humanity to Mars”? Surely you don’t have to take all the humans to Mars.

We’d all agree that Europeans (non-exclusively) colonized the Americas, but not all Europeans went and not all had the opportunity.

You compared a tangible item being divided amoung people to an achievement for humanity as a species. They are two different things.

That's my issue

The Americas were divided among people (original inhabitants, and later colonies), and many countries & people weren’t recipients. But I’d still say that humanity has reached America.