If it's so obviously good, then why aren't people paying out of their own pockets to help out?
I'm going to anticipate your answer: because they're too selfish. But is there any reason to believe that our elected officials are any less selfish? Look at the narcissistic idiots we elect - and ask, are these the people whom you really want holding the purse strings? I often see complaints, "petition congress not to defund science". Well you know what, scientists shouldn't be so darned entitled, it wasn't their money to begin with. Putting their faith in the continued patronage of a capricious bunch of authoritarians beholden to questionable special interests may not have been the smartest way to secure a sustainable (or a moral) stream of funds.
In the end, taxes are backed by "if you don't pay them, you're gonna be taken away by agents who will throw you in jail". That's blood money you're taking. Deficit spending, which is governments do these days, is even worse - at least with taxes there is the pretense of the voter having a say; when you borrow money on the credit of the nation - you are mortgaging the assets of future generations, who cannot go back in time and cast a vote against spending their money on a stupid idea.