What I’ve always found curious is that, while you pay interest on government debt, you don’t earn interest on capital reserves. This is obviously unrealistic; you’re not squirreling away stacks of hundred-dollar bills in the White House basement, but investing government surplus into foreign bonds (e.g. China) or local ventures (e.g. Australia). You should be able to use your reserve to fund mandatory spending like government pensions, and the elderly should be happy that their pensions are secure. That’s realistic. Currently, if you have any reserves, it makes sense to cut taxes immediately.
Now, to avoid players from building up large reserves with which to fund the rest of their spending (taking taxes out of the equation), a situation might occur for countries with a high reserve to GDP ratio: lack of venture capital. Due to the government controlling a large share of the economic capital and using it for safe investments only, riskier startups have trouble getting funding. The result is a big hit to GDP, the self-employed, and capitalists.