If you replace all social welfare programs, you get around $3T/year, or $500/month for everyone (universal). That $500 now needs to cover all medical expenses, housing, and food for the subset of people who used to exclusively receive those benefits. That includes completely eliminating social security, which currently averages $2.5K/month.
Meanwhile, the vast majority of people receiving income (the universal part), would have a portion of their income previously provided by wages replaced with money that used to be used for social services for those that either needed them (based on the current definition of need) or had “paid in” with the expectation of income at old age. Who is benefiting from this?
Your average, averagely healthy non-disabled person shouldn't need or receive or need more than UBI. There are always some that need extra support, but they are absolute minority.
But, for example, in the US something like 70%+ of the total Federal budget is already spent on programs for the poor (Medicaid, EITC, SNAP, school lunches), the elderly/retired/disabled (Social Security, Medicare, government pensions) and debt service.
Unless UBI proposes to take funding away from those who are already poor or already retired then where exactly is the money coming from?
Meanwhile, the vast majority of people receiving income (the universal part), would have a portion of their income previously provided by wages replaced with money that used to be used for social services for those that either needed them (based on the current definition of need) or had “paid in” with the expectation of income at old age. Who is benefiting from this?