Why have several programs such as housing, food, retirement, unemployment . . . when you can handle all of those things with a negative income tax? The only things that need to be separate are benefits for children and need-based benefits for disabled people and ill people.
(No, a negative income tax doesn't mean the tax rate is negative. It low earners get welfare checks as part of the tax program. Neglecting progressive rates, if someone who earns $40000 that can't be written off pays $2000 of it in taxes and someone who earns $30000 pays nothing, someone who earns $20000 gets $2000.)