Humanity will never reach the stars.
Why? Well, yeah, why? Humanity will very soon be able to exist fully in virtual reality. Once we have perfect simulation of reality, then our imaginations of what might be in the Universe will greatly exceed what is actually there. Our stories will be much more alluring and billions of times cheaper to explore and investigate. As soon as we can “think” we’re exploring the solar system, the galaxy, and the universe, while being immersed inside VR tanks, or suits or neural implants, then why would humanity spend the time and money _actually_ exploring those spaces?
The scientific community would, one suppose, continue to pursue exploration and discovery, building bots that traveled as fast as they might to other star systems. But the billions of commoners who were more than happy to just sit back and imagine they were on another planet, eating exotic foods, speaking and interacting with bizarre aliens — why would they ever want to risk actually traveling to such locations?
They wouldn’t. And the funding for such actual excursions will dwindle as VR sims become more and more real. The economic reason for exploration of other star systems will fail to compare to the economic reason for delivering an even better virtual world here. And face it, the human imagination is nearly inexhaustible. It’s unlikely that the universe can beat us in the extraordinary portrayal of diversity of life and systems. (Unlikely, not impossible.)
If humanity lives through the next fifty years (no CMEs that destroy civilization, no plagues, no nukes, no asteroids or super volcanoes) then by the time we could actually GO to Mars, we won’t have to, or want to — at least not to experience it. We’ll be able to do that right in our Almost-There-Capsules.
This is one of the solutions to the Fermi Paradox. And, really, humans are almost there.