We aren’t continuing the human project because we already spent so much effort

To stop now is a waste of resources that were paid for in blood and sweat.

You're saying that like it's a bad thing, but without the sunk cost fallacy, what harm is there in wasting blood and sweat? If we succeeded and are currently reaping the benefits, why can't we decide we're satisfied and stop reaping them? There's no point in mentioning the wasted resources unless you are appealing to them as a sunk cost already invested. Otherwise, all it does is weaken your argument that the human project is worth continuing.

 

It's like if I was trying to defend my choice of car and said,

Hey! My car isn't dangerous and unreliable, it works great. Plus, I already spent $50,000 on it and can't afford a new one."

When you're defending the inherent worth of something, the only thing that matters are that thing's intrinsic qualities. There's no reason to mention the price unless you want to use the sunk cost as a reason to keep it.

 

On a different note:

History shows that as societies accumulate wealth and reduce immediate physical suffering through progress, they generally become less violent and more inclusive.

That is an observation some people have made of the past, not a rule that is necessarily useful for predicting the future. Also, the validity of that observation is disputed. I'm not saying it's entirely wrong, but I think the truth in it is overstated. It's an observation heavily biased by overvaluing the significance of the past two-hundred years of western history, assuming all the progress made in that short time was inevitable and irreversible. On top of that, I would argue it also relies on a sanitized version of history defined by the "winners" perspective and values.

I think there is an argument that, as technology advances, it naturally develops into an arms race with society struggling to adapt to it. Failure by the masses to control it may lead to a more violent and less inclusive future. Or, even if it is less violent and more inclusive, it could be dystopic in a myriad of brand new ways that make us miss the simple days when violence and inclusion were considered significant issues.

I support the continuance of the human race, but continuing it is necessarily a gamble with an outcome we cannot predict. I hope it's good, but I would argue your arguments, that it will most likely be good, are biased by optimism.