Are there any real studies done in this field that factor in which percentage of the population has to be working for the system to be sustainable? And what wou

Are there any real studies done in this field that factor in which percentage of the population has to be working for the system to be sustainable? And what would be the most reasonable source of funding this project? I'll admit it, the idea to be paid to do nothing is completely strange to me, and my basic instinct tells me that unemployment would skyrocket, but I'm willing to forego all of that if the system proves to be more efficient and slashes the total cost of government and reduces the tax burden as many of these articles suggest.