Many people would not receive this money from the government as their taxes would be more than the $10K payment. 160 million Americans work, and likely half would receive little or no money, and only the bottom two quintiles of income earners would earn the full or close to the full amount. So probably only cost around $2T, or about 25% more than Social Security and Medicare/Medicaid combined (although this would only replace Social Security).

Very expensive, but doable in a world where our representatives weren't corrupt to the hilt.

Not sure what is an equitable solution for children, but giving the full amount per kid seems grossly unfair.