For what my opinion is worth, Golden Age SF, and the current Human Wave are rooted in optimism to begin with, and I think if you don't have that optimism about the future, you're going to have a damn hard time faking it. Unless you want to spend your career filing the serial numbers off dead writers' works, slapping the plot and characters into a Procrustean bed of political correctness, and making people regret they ever picked up your book3 - but hey, it's your career. Do what you want. Just don't bitch and whine and snivel when other people don't find your remakes inspiring or entertaining. On the other hand, if you want to take the old stories' plot and characters and bring them up to date so it's not obvious the story was originally written in the 1940s, that's different - and, IMAO, better.
To sum up all this, art is the product of a society, and great art has an impact that stretches across the generations. This is the greatest sin of the Left, which has tried its damnedest to destroy the legacy of Western Civilization by refusing to pass it on to those they claimed to be educating and by claiming it was worthless since it was all written by "dead white European males". As if nobody but Anglos could appreciate Shakespeare, nobody but Germans could appreciate Bach or Beethoven, and nobody but the French could appreciate Delacroix. Asimov, Heinlein and Clarke inspired a generation of engineers and scientists, and twenty years later, Gene Roddenberry's "Wagon Train to the stars" sparked a cultural revolution and eventually a quiet victory in the culture wars that made SF and fantasy acceptable fare for everyone, not just the socially awkward outcasts who'd once found refuge in "escapist literature". If Stephenson wants to inspire people to do great things, he needs to pitch his inspiration at the part of society most receptive to it, the subculture of geeks and nerds and ordinary folks who want to live in the billion-volt limitless future with Klingons, Vulcans, a Terro-Human Federation - and above all, hope.
*Something I'm going to address at length in next week's book review post, which is why I'm not going into it here.
** Which I frankly don't think is going to happen, given that they're all besotted with Intersectionality and probably regard "getting big stuff done" as just another excuse for Patriarchal Oppression.
As if the whole push was a cover for building a mighty space-going dreadnought to be named the Enormous Patriarchal Tool. (h/t Larry Niven for the ship name. I think)
3Fuzzy Nation, I'm looking at you.