People who are specifically not employed because they aren't motivated to do anything at all don't seem to be the best sample for what average people could do if they had more free time during their waking hours.
It seems unlikely that the most motivated people will take up UBI; the most likely UBI recipients are those who are marginally employed, and likely marginally motivated.
It seems unlikely that the most motivated people will take up UBI; the most likely UBI recipients are those who are marginally employed, and likely marginally motivated.