The idea behind basic income is to remove day-to-day struggle from people's lives. If only they didn't have to worry where their next rent check is coming from, then potentially a huge groundswell of human capital could rise out of nowhere and carry us all into a new age.
But we don't need to actually implement basic income in order to test that out. Plenty of people already receive checks from the government every month that they live on, in exchange for no real work responsibilities. Like, a whole lot of people. There should already be a not-so-huge wave of accomplishment coming from all these people. Not to belittle them and their abilities, but there isn't. Just about everything that we consider a real advance comes from people working the system that exists using their own ingenuity, not from people allowed to escape the system by providing them an inalienable source of income.
Modern Western societies are rich enough that smart, motivated individuals can mostly rise to the level of their own ability. To do better than that we need to build a better society, not just make the one we have richer. Basic income could be an important step, but it's only one step.