Also “will people be more likely to start their own enterprises if they have basic income?”
That destroys your argument.
edit: the whole system is more complicated than this, of course, but the point here is that this safety net is permanent – you can not lose it even if you are unemployed for a long time (recently, a tiny reduction of welfare payment was introduced for those who do not meet certain criteria for activity; however, you are in any case entitled to certain level of income, and government-paid rent, etc., in any case.)
Feeling like you can loudly assert things not in evidence is a sign of some pretty tall ideological blinders.
But a hypothesis is just that: a hypothesis, not a fact. There's plenty of existing research on how changing unemployment benefits change work incentives (answer: not too much), but it's also true that longer time horizons might change that answer. That's why experimental tests are needed.
That's not quite the question. The question is, will unemployed people look less for a job if they're guaranteed free money even once they get a job, compared to the status quo where they are guaranteed free money (for awhile) that stops once they get a job.
There's also a follow-up question, that is something like "Will people on permanent disability start getting jobs if you stop punishing them by permanently taking away disability payments if they get a job?"