All those years of varying tax rates, like you said up to 90s%, 50%, 30%, it hasn't really mattered much adjusted for inflation etc, the tax dollars the federal government took in has always remained about the same.Not really on topic, but we have a lot of undertaxed people and businesses in the US paying poverty wages and taking in government subsidies. We've had marginal tax rates as high as 92% in the US history and the country did not fall apart, including during other pandemics. There was a 50 year period up until the 80's were the marginal tax rate was over 60%. Right now we have a marginal tax rate around 37%. Higher tax rates also often coincide with higher per capita GDP, benefitting the economy as a whole. There's a balance to be struck here and during a national emergency I don't see why we couldn't close tax loopholes and raise the marginal rate to what it used to be when my parents were my age or what it was during our last national pandemic.
https://www.taxpolicycenter.org/statistics/historical-highest-marginal-income-tax-rates
https://www.macrotrends.net/countries/USA/united-states/gdp-per-capita
https://www.epi.org/publication/ib364-corporate-tax-rates-and-economic-growth/