I think your QED is premature.

You're using arithmetic to model your scenario. I contend it requires differential equations.

For example, Mark Zuckerberg owns ~500 million shares of Facebook. If you only use arithmetic (multiplication) of share price, you get ~$40 billion. That's a theoretical number that journalists can calculate but it's not an accurate model of reality. If he was to really liquidate all those shares to 0%, his final sum would be much less than $40 billion. When he sells the first 10 million shares, the market will see that as a "signal" and react which sends the shares down in price. The final 10 million shares could be $1 each if the market was sufficiently spooked about his selloff. To model that requires a differential equation instead of arithmetic.

So to apply that logic to your example:

  GDP of USA: 1.5 * 10^13

This assumes GDP stays the same if millions of people decide to quit working because they have basic income. If we think GDP will drop, we need to model that somehow.

  Basic level of sustenance for a person in USA: 10^4

This assumes that prices will not go up significantly as landlords, grocery stores, etc respond to everyone having basic income. How can there be extra money or "inflation" if we're just shuffling money around? Well, women with children qualify for welfare+foodstamps but single childless men typically don't qualify for anything. Perhaps they live with their moms or sibling. Also, prices will go up because there are less low-paid workers manning the stores. I don't claim to know all the complexities of side effects but to think prices won't change at all doesn't seem reasonable.

Lastly, I do think the USA has enough "wealth" to provide some type of basic income. The question is what the USA can "afford" and that word can have several interpretations.

The level of "afford" I'm thinking of is a scenario where the USA suffers zero productivity loss and the middle & upper class do not see a decline in the standard of living. I'm not convinced that the USA can provide a dignified level of basic income without affecting the goods & services the middle class' enjoy today (points back to claims of a constant GDP instead of a declining one.)

Show some Diffy Qs, explain the assumptions behind each of the variables, and throw them into a Google spreadsheet.

Fewer words, more math.

Cute. But it doesn't apply to me.

I'm not the one trying to quantitatively prove whether it will work or not work. I thought you were. So far, your mathematics model and your assumptions behind it are unconvincing.

LOL. You made me chuckle a bit at least. Thanks for that.