Well, we won’t find out if we didn’t try, would we? We don’t need the stinking warp drive to get to Mars.
There may well be nothing on Mars that’s not available on Earth. BUT we will have shitloads more of it. Asteroids also have craptons of rare minerals that we can’t dig out in abundance because it’s sunk into magma. Earth is expensive place to fly off of because it’s heavier. No, Earth isn’t Mars nor Moon - it offers plenty that Earth alone cannot provide.
The perverse nature of humanity is that the very fact that earth may be our ONLY nest, we will take it as a zero-sum game and fight over resources. Yes, we’d better stop crapping in our back yard, but space exploration and sustainability are not mutually exclusive, and KSR is just trying to grab attention because he wrote a book about Mars long time ago and wants some sales.
