I agree the most important ultimate aim of space travel is human colonization. But we are probable at least a century from meaningful human colonization within the solar system, and several centuries from interstellar colonization.
To put it bluntly, the technology to overcome the primary hurdle in those endeavors have not advanced, even incrementally, too much since Sputnik. To bring those endeavors closer required considerable breakthroughs in basic science. So the best use of resources to bring truly meaning manned space travel closer is not to squander available resources on prestigious but ultimately meaningless manned stunts like lunar or mars landings now, but to invest the funds in basic and applied science to bring forward the date when we would acquire the scientific and technological skills to make manned space travel economic.
To put it bluntly, the technology to overcome the primary hurdle in those endeavors have not advanced, even incrementally, too much since Sputnik. To bring those endeavors closer required considerable breakthroughs in basic science. So the best use of resources to bring truly meaning manned space travel closer is not to squander available resources on prestigious but ultimately meaningless manned stunts like lunar or mars landings now, but to invest the funds in basic and applied science to bring forward the date when we would acquire the scientific and technological skills to make manned space travel economic.
