Why would you do that?
Two centuries in the future, the benefit of going to mars will be obvious, because we will have progressed and gain things we don't know about now.
That's how humanity works. We try crazy stuff. And a lot of it is stupid, expensive and dangerous. Plus the result is disappointing.
But eventually something pays of big time.
And everybody says of course we should have done it retrospectively.
It's like people asking why we are still making purely theoretical math research. Surely it's no use, and it's expensive.
I have no doubt many people opposed to the moon landing as well on those grounds.
I expect fully the comments to answer "but this time it's not the same because...". But it's never the same.
It's always a different situation. That's the point.
That's what discovery is about.