How would you know it doesnt work, it hasnt been implemented. What are you basing that off of? Right now welfare is not conditional, if your poor you get welfare, Which doesnt work, which proves that non-conditional aide doesnt work, so why would UBI (taking the current system to a more extreme state) suddenly start working?
Rather than doing more of the same that we already know doesnt work (unconditional help) perhaps try it the way I propose first so you actually have some data to judge it.
inb4: In my case im basing it off data, personal data in a way that isnt exactly the same, but its an educated decision. I spent my life taking many homeless and poor people into my house to get them off welfare. I've seen success and I've seen failure and im basing my position off what ive seen works.