That's not even close to true. Basically every study on UBI, everywhere, has shown that either more people work, or employment stays about the same, but in each case happiness and health go up vs the control.
Since it's very clear you haven't researched your claim whatsoever - why are you making it? Why would you say something so wrong with so much confidence?
If we have the technological means and capability to reduce employment to 10% - why wouldn't we?
Is it so impossible to imagine a world where people only work when they want to? Where the jobs that "no one would do if they weren't desperate" just pay very well instead?
Also, if you really think every UBI study is fundamentally flawed, feel free to design and run your own. Until then, maybe you could do better than waving a hand and invoking a hypothesis to try and invalidate literally every study that speaks against your claim, lol.
> Also, if you really think every UBI study is fundamentally flawed, feel free to design and run your own.
All temporary studies are fundamentally flawed, because people act based on their permanent lifetime income. It's not like I can design it better, it's just not something that can easily be studied (on any reasonable time scale).