It's possible (maybe) but since no one has done it, or even come close, then it's pretty unlikely. If we could make machines that think like we do, we'd sure as hell do it, because that shit would open up frontiers like you can't imagine. Free anti-gravity, or eternal life, are kinda similar - no reason they couldn't be discovered (maybe) but it's looking pretty unlikely since no one's done it.
I fail to grasp this line of thinking: because it hasn't been done yet, it will hardly be done next. It is as if a XIX century Londoner tells me "Well, maybe we can get to the Moon, but since nobody's done it, it's pretty unlikely". And yet, a centurysome later... It hasn't been done yet because we don't have the capability, much like XIX century Britain didn't have the capability to launch a rocket into space. Time goes on, and opportunities arise, and so far, humanity's been pretty grasping about them. We now have an almost-instantanious information exchange between any part of the world, food production system capable of feeding billions, we can travel at astonishing speeds all across the globe and build both deep underground and high above it. Keep your mind open about what hasn't been done yet.
We're in agreement - you saw how I said "It's possible (maybe)", right? Someone 100 or 200 years ago would have been 100% CORRECT to say "it's pretty unlikely" that they could go to the moon! I think it's also quite possible that we WILL develop a way to have immortality - and I think that possibility is on a par with creating human-level intelligence artificially. For either, there's no clear path for how to get there, so barring some unforeseen breakthrough - it's gonna be a while, at best. I try not to engage in wishful thinking.