I think a large part of the issue, ignoring the self-interest one (certainly those of money will argue that their taxes should be less) is that both the supply and demand side can interfere with the proper functioning of the economy

My quick take is that during the 2008-ish great financial crisis, those in power were children of the 1970s supply-side shocks (demand>supply resulting in shortages and inflation), and used precisely the wrong tool to handle the demand-side shock of the GFC: interest rates were zero-to-negative, indicating a surplus of investable cash and no place to put it to work, and policymakers responded by...cutting everything on their side to the bone as well (austerity). At a high level: the economy was literally trying to pay the government to spend money on productive investment, but this once-in-a-lifetime opportunity was largely squandered