If up to me, I would put quotes on "humans", because we aren't and never were a static, unchanging thing. Without technology we did quite a bit of changing, and with it, especially at the present rate of acceleration, what stops us from slowly but surely changing the definition of human?
Take each reason supporting why humans cannot leave the solar system, and ask, over time, through obviously controversial modifications, why we couldn't mangle ourselves sufficiently to challenge each of these reasons.
And on the energy side, can we really predict that? We have government officials testifying on witnessing UAP, with a high probability that if they did really see anything at all, it was of human origin. Whatever that tech is, if we are not factoring it, then the "never" becomes a bit subject to questioning.
What is fringe today, and either taken for granted, dismissed, or simply overlooked, can quickly change, especially with colossal compute behind it. I often imagine how far we'd be if we actually gave that whole 'capitalism' thing a chance, without all the putrid patent slop, and other little complicating factors eg, Invention Secrecy Act of 1951 (35 U.S.C. §§ 181–188), 28 U.S.C. § 1498, etc, not to mention greed, monopolies, and dozens of equally formidable factors.
Even a subtle difference of governance can offer a subtle, but reasonable example of how development is effected by policy, as seen with China.