I'll be honest. You had me in the first half, but then: "... the hypothetical paradise it produces full of wonderful artists and musicians and programmers creating text editors rather than CRUD apps ..."
Who willingly endeavors to write text editors in 2024 when acme(4) exists?
I jest. More seriously though, if the measure of one's value to society is in their ability to crank out CRUD apps, I'm appalled. I want more dishwashers, more plumbers, more framers, more joiners, more cooks, more babysitters, more stonemasons, and the only way any of that kind of hard labor is sustainable is if there's a cushion to fall back on to recuperate. Bodies break. They break more catastrophically when the damage is continued and sustained over time.
I want my girlfriend to feel free to take on domestic work full-time with the knowledge that, no matter what, she'll be paid for it and that her domestic labor contributions, as informal as they are, are valued monetarily without my having to make up the balance. Likewise, I want that there in case I myself want to take up those domestic responsibilities for a while.
These are two cohorts that literally cement the foundation of society, let alone our trade system, not a cavalcade of keyboard cowboys wrangling Ruby on Rails. I want UBI for them because, without them, the entire project literally crumbles.
The UBI problem, and the problem in your post, is you're engineering starting from what you want, and then assuming that there must be a solution to get there.
You have to start with what you have and build from there.
This is a subtle point and it may take some meditation and thought, possibly ever over some months or years, to understand what I mean. But if you are an engineer, life will hand you opportunities to see what I mean. You can't write down a list of requirements, then assume that exact solution exists, and then burn for it full speed. You must always start with what you actually have and the options you actually have.
The thing that makes perfect sense to me, but you would consider ironic, is that while you may accuse me of this and that, lack of imagination, lack of dreaming, lack of belief, whatever, my way builds better worlds and your way builds failures. I don't follow this path because I don't also see the temptation to build dreamscapes and live in them, I follow this path because it's the one that works.
I am, in fact, not an engineer; I trained to be an actuary. (Though, I guess if one squints enough, the operations research electives look like industrial and systems engineering.)
I consider UBI less an engineering exercise with requirements that feed into the engineering method and more one of ratemaking and claim severity against an entire trade system. My only goal is to put a dollar amount on a loss event (and get some quantification of how many loss events occur over time while we're not looking). What anyone does with that is up to them.
Use of the second person was certainly a choice.