"Because the government isn't, (or at least shouldn't be) beholden to short term interests in the same way those other classes are". A Government is made of people. "Shouldn't" doesn't mean "Isn't". You need to convince me that it "Isn't".
"Companies will happily destroy everything around them, poison and impoverish entire nations if not reined in, just to turn a quick buck." I disagree. What's the point for investor to make money and then die of pollution or die in a fire. Yes, there are bad apples and stupid people, but you can't design a system that prevent people to do things because there are some bad apples. Look at the big tech, they are mostly investing voluntarily to reduce fossil fuel dependency. Of course if there is a market failure that really can be solved by the Government and that would otherwise kill us all, then I'm in favor of (indirect and market based) intervention.
"People are extremely short-term, local thinkers in general." Disagree, people have different plans, some shorter term some longer term. Also why would they have short-term thinking in the market but long term thinking at the election?
"A government, under the purview of democracy, is needed to try to balance these things out and help a society actually operate" Very likely so. Although there are some ANCAP proposals I find interesting like the one form David Friedman, I'm not convinced it would work in practice. However my ideal Government doesn't balance anything (I don't think it actually can without making more harm than good). It instead define the rules and what constitute private property, but it doesn't decide how to allocate these resources. That would be left entirely to the market.
