Let’s disregard the politics for a second, which makes it dead on arrival.
It’s not as simple as saying, “let’s set it at 10k per person. 320 million people in the US with an 18 trillion dollar economy means we’re only asking for ~18% of GDP to fund this bad boy, minus any state and Federal welfare programs we deem extraneous with this new entitlement!”
The problem is, GDP is not aggregate personal expenditure (consumer spending), which is what we’re really talking about here with a UBI. Personal expenditure makes up about 70% of the economy. So when we talk about relative amounts, it has to be measured against that and not GDP.
So now it’s 3.2 trillion against 12.6 trillion, which would be just over 25% of all consumer spending. Let that sink in for a second. On top of the things the Federal government already shapes the way people spend money that would not be eliminated with the implementation of a UBI (student loans, Medicare, Medicaid at a minimum), you’re asking the country to rearrange 1 in every 4 dollars that people spend over the course of a year.
This is on top of the lost wages and productivity we’d get as people drop out of the workforce. Now let’s add politics back in. Obamacare was a political fight that resulted in the largest loss of House seats since 1938. And what was the fight ultimately fighting over? A sixth of a sixth of the economy.
Bill Gates is 100% correct in the fact that we are nowhere near ready to discuss, let alone implement a UBI. Maybe 30 or 40 years from now. Certainly not today.