And what for if I may ask?
And please don't say "technological development" or "colonizing space".
ad Development): Most of the tech that needs to be developed for this, is what is commonly called space plumbing: Figuring out ways to make human bodily functions not immediately fail in space. Next to none of these technologies benefit humanity at large in any way. Also: We keep coming up with amazing new tech all the time, without the extra cost of strapping it to a human and shooting that package into orbit.
ad Colonization): There is nothing in our solar system to colonize. Period. Everything other than Earth is less hospitable than Earth would be after a thermonuclear war, by a huge margin. Terraforming another planet is practically impossible fora species that still has to count the kilos for every launch.
And as for the one goal that makes sense, which is exploration: We have a perfectly reliable form of space exploration: Robots. And they are much better at it than we are, for one simple reason: They don't require space plumbing.
There is exactly ONE reason why Apollo was manned by people instead of robots: Because computers, electronics and robotics in the 60s were not up to the task. If todays tech existed back then, I would bet the Apollo rocket would have had exactly one passenger, and that would have been the Lunar Roving vehicle.