UBIs have to be universal (most proposals are not Universal, they are just Basic Incomes, Italy just created a fake one called "reddito di cittadinanza" literally translated as "citizen's income")
We may have public healthcare and schools, but most parts of the world, including the US, don't.
We also have universal public welfare, unemployment benefits, public housing, public transports, in Italy we also have mandatory car insurance, it means everybody has to pay for it, it also means that the prices are heavily regulated and must be affordable and - most of all - non discriminatory (you can't set a price based on personal data and background of the single client and there's an authority reviewing the methodology).
These are all things that in US don't exist or are seen as "socialist", hence bad.
If you add an UBI but don't fundamentally change the way the system works it won't make a difference, companies will just adjust the prices accordingly because more money will be in consumer's pockets (the market is always right! right?).
The only real point I can make is improving on the things that already work, just throwing money at problems won't solve problems.