UBI is mostly just socialism with a fresh coat of paint. To understand why it fails, you have to understand what money actually is. Money isn’t some mystical resource that appears out of nowhere. It is a way of representing favors. It is a much more efficient way of trading a website for a bag of potatoes than actual bartering, but it only works if it represents real value created by someone.
When the government takes money by force, they are essentially claiming ownership over a portion of your life. If you work for several months out of the year just to pay your taxes, you are, for those months, essentially a slave. As that percentage climbs, the people who actually create things eventually realize the trade isn’t worth it. They stop building. And when the makers stop making, the people in charge are left with a choice: let the system collapse or start forcing people to work. That is how you end up with real dictators.
Most people who advocate for things like UBI have never actually participated in the “maker” side of the economy. They think of the economy as a pile of goods that just exists, and the only problem is how to distribute it fairly. They focus entirely on consumption and ignore the mechanics of production. But you cannot have consumption without motivation. If you kill the incentive to produce, the whole structure disappears, no matter how many clever names you give it.