Growth in inequality correlates very nicely with expansion of the money supply. My theory is that when you print money, most of the new money finds its way into the pockets of the rich. Even though we print new money to pay for government spending (via bonds) - eventually all that new money trickles up to people that own assets. And the people that own the most assets gain the most new money. I think we should return…
Consider that the federal government collected revenues of $3.5 trillion in 2019, or more than $10,000 for every person in the country. State revenues combined were more than $1 trillion in 2019, for a total average tax liability of about $13,600 per-capita. I don't see a realistic way to double or triple that revenue number while taxing income alone (and citizens would naturally demand a commensurate increase in government services if such a tax increase applied at lower-income levels).
Taxing wealth or ownership in companies is another route, but individuals who own any notable percentage of a public company are naturally very mobile, and could easily change their country of residence to somewhere more tax-friendly (like former Google CEO Eric Schmidt may be planning).
It seems like a difficult position to be in for the government.