You clearly don’t understand how much engineering, medicine, materials science, and other research happens because of manned spaceflight. Plus, there are things you can only study in microgravity.

NASA budgets definitely look big, but the value of the technology produced in that process (and consequently released to the public) dramatically outweighs the input. This has been proven over and over again.

You’d be surprised how much of that tech is used for precisely the purposes you want - feeding people sustainably, healing the sick, etc.