Fair points but you and the other commenter are, in my opinion, thinking too near-term. On the scale of hundreds of thousands to millions of years, evolution starts to become a factor. The beings that leave earth to live elsewhere, on that time scale, may have been human once but would have evolved into something different, hopefully more suited to environments on other worlds. And we’re not even close to the destruction of earth by the sun, which is on the order of a billion years from now.

That’s more what I meant by inevitable. Our curiosity brought us to the stars early, but we have the time here on earth to invent, adapt, grow, and change before the hard stop of needing to leave earth…assuming we survive what earth throws at us (and what we do to it) in the nearer term.