To answer your question directly, that $180B would fund 7.5 years of the SNAP program following the increase in benefits during the pandemic (https://www.usda.gov/media/press-releases/2020/04/22/usda-in...). But that assumes you could actually liquidate all $180B and have the same purchasing power as what it represents today. That isn't actually possible since Amazon's stock would crash once Bezos starts to sell large quantities of stock.
All the billionaires in the US combined only have a wealth of $4T (https://news.yahoo.com/wealth-us-billionaires-soars-during-2...). You could take 100% of it away and the Government would spend it all in an instant - after all, look at the state of our deficits and debts (https://usdebtclock.org/). And once all this spending is done, we will have removed the biggest incentive for future entrepreneurs to dream big, take risks, and build. And with government inefficiency, we probably wouldn't have much to show for that spending either, except slightly less envy among the masses who are complaining about inequality despite having great standards of living.
The US government spends roughly $11k per person pr year for health care. So back of the envelope math gives me that Bezos's $180 billion could but everybody in the US an extra 5% worth of health care for 1 year.
And to compare these big numbers against proposed spending, Medicare for All could cost $3.4T/year (https://www.theatlantic.com/politics/archive/2019/10/high-co...) and Green New Deal could cost $18T-$93T over a decade (https://www.factcheck.org/2019/03/how-much-will-the-green-ne...). So if we're generous and take the low end, we're looking at around $5T in new spending a year.
All the billionaires in the US combined only have a wealth of $4T (https://news.yahoo.com/wealth-us-billionaires-soars-during-2...). You could take 100% of it away and the Government would spend it all in an instant - after all, look at the state of our deficits and debts (https://usdebtclock.org/). And once all this spending is done, we will have removed the biggest incentive for future entrepreneurs to dream big, take risks, and build. And with government inefficiency, we probably wouldn't have much to show for that spending either, except slightly less envy among the masses who are complaining about inequality despite having great standards of living.