Plus UBI probably creates a disincentive for work. This is not just some hypothesis. In trials of UBI people receiving UBI worked less. Fewer people working -> less tax revenue -> less money available to finance UBI.
UBI isn't a panacea or a route to utopia. Jobs can't be optional until we have some sort of robotic labor force, which is a long way off.
Not if you spend it on office equipment. The $20k buys you $20k worth of free time in your life to work on your personal projects, ideas, hobbies without your life falling apart as a consequence.
That's enough time to set up a small leather-working shop in your garage, or build an app, or start a podcast, or write a few chapters of a book.
It is a mental state and a type of personality. You can be one and be successful starting with 0 dollars.
Entrepreneurs don't even need office space, and can get going with extremely limited equipment.
Honestly you have a profound misunderstanding of what an entrepreneur actually is.
Isn't that around the amount YC typically puts into a project?
Hasn't the internet proven how cheap entrepreneurship can be?
Not having to burn yourself out just to feed and shelter yourself would afford you vastly more opportunity to find a niche that you can make an extra buck in, if you're inclined and motivated that way.
I don't see why this is such an un-obvious notion, or why people seem not to think that could net us a far richer economy — of goods, services, and ideas — than the one we've got, where you on the whole only get what someone who already has money (either the founder or their backers) decides to make.
Or try your hand at entrepreneurship, since you've got a net. Or write a book, which you turn into passive income. Or, or, or...
A UBI should take us to a place where jobs are optional. This is an unambiguous net good, IMO.