Many people share your view, though, and it's a shame. We have all of private industry to focus on short term benefits. Grad school is one place where the grinding expectation of immediate return-on-investment can be suspended. PhD students take low compensation hoping they can use curiosity and passion to direct their research. Increasingly, that's not the case.
>> appreciate the fact that the public is giving you grants and funding because the alternative is you get nothing.
This is cutting off the hand to spite the face. Taxpayers get an _unbelievable bargain_ for the work of PhD students and postdocs. Gutting research funding won't hurt them for long, they'll easily move on to much higher paying work, it's future society that will suffer.
I'd argue you get the best and most significant contributions to society in the long run with stable government funding of basic research. Don't believe me? Ask Steven Chu, Nobel Prize winner and energy secretary:
"letting scientists chase down interesting things" as per the OP's comment is how the "human knowledge base" grows in the first place.
Besides, who would decide what research is useful to pursue, other than the experts in a given field? If you don't really understand a research subject, how can you figure out whether it's useful or not?