Because nobody ever accepts more work or responsibility for higher pay to afford more or better things. Most people work just enough to pay for rent and groceries and are perfectly happy with that.

Difference between UBI and this is that you get paid the minimum for living, which would mean him being able to live like this would only be possible for a short amount of time or with really restricted funds

Love that you're getting down voted but we had something approaching universal basic income in my country trough wellfare plans that were not exclusive with each other and had super lax requirements (since corrupt officials would take a cut of them) and it resulted in a very marked increase in poverty and a very marked cultural decline in work ethic on the lower classes

Why work or study when you can just stay at home and get paid enough to survive if you vote for the "right" candidate. People love to dream about theorized ideals but reality is often more complicated