By "basic income," I assume you mean the government pays everyone enough to live. Welfare by another name.

What keeps people from just taking the money and doing nothing?

Some fraction of people will probably always want to work because a job makes them happier, or they desire the luxuries that the increased income makes possible. But in the time between now and the techno-utopia where robots and computers do all the work, how do we know that this fraction will always be big enough? Why won't our society won't collapse due to too many people opting to live on the public dime, and there not being enough workers left to produce the food, clothing, shelter, etc. needed by the non-workers?

Isn't this basically how communism collapsed?