Manned spaceflight is a waste of money because the cost/benefit isn't there.
With the advances in electronics and robotics, unmanned spaceflight becomes steadily cheaper and more valuable - and the value of pure science is impossible to predict - if you know what was valuable to know you wouldn't have to go look for it.
We grossly underinvest in pure science, business can never replace government because pure science can't be patented and has little present value as an investment (i.e. intellectual property that can be controlled and moniterized), but huge social value. As you move from pure science to research to development, the government's role should decline as you get closer to commercialization.
Government research not only creates knowledge, it creates knowledge workers, i.e., university research is where you train the guys who go to industry to create new products - what company can spend 4-5 years teaching theory and provide hands-on internships for skills they may or may not need in a decade? But once these young researchers are trained, they will gravitate to the industries where their training has the highest economic value.