We've added a change; of course the world will change! But yeah sure if we introduce UBI and hold the rest of the world the same then UBI will have an unobservable effect.
> If it's possible to optimize, why didn't they do it before?
I mean people aren't actually rational so there's a million angles there. However, the cost of a janitor is going to go up with UBI as the opportunity cost has increased.
> then doing low-paying job part time should also cover these basic needs. Something in your logic is not adding up.
No, I just don't think you understand the world around you. Have you never heard of remote nomads? Plenty of people work full-time for parts of the year or part-time all of the year.
> Geologists not needing to hide information, because they don't need that money to survive is opportunity cost how?
Giving the information away for free costs you the money that you could've gotten for charging for it. When you need that money to survive then you have to restrict access. When you don't then you're able to volunteer it.