There is already more art and philosophy than there is a demand for and there is not even a UBI. Increasing the supply of art and philosophy won't change that (to say nothing of the other activities people can choose). I don't want to create an incentive for people to drop out of jobs to spend their time in a worthless activity. By worthless I mean, they have created nothing valuable. It will create a loss of productivity and a decline in skills. Of course, if you do this on your own time and money, have fun.