Basic income experiments usually game it like this: We will give you x years of payments monthly for just being alive.
Then they see what happens. The problem is, policy has one huge difference. It doesn't end.
The difference between, I'll give you 2 years of payments monthly and then you'll have to take care of yourself the rest of your life is extraordinarily different than, I'll give you monthly inflation adjusted payments for life, there will be no point in the future when you will need to take care of yourself again.
Think about the FIRE movement. People are working to create an early retirement for themselves with the government not offering it. There will certainly be a percent of the population who retires with basic income.