Joseph Gordon-Levitt is a GREAT Actor Who - Like Many - Struggles to Believe in the Benefits of AI+UBI

Joseph Gordon-Levitt has said that he thinks that broad AI job replacement with some kind of UBI seems to diminish or even erase human endeavour and worth:

However, I suggest that replacement of labour markets with AI and AI GPRs sounds great if one realises that it doesn't remove human motivation or enjoyment at all. Such an outcome does not have to follow. 

Moreover, humans previously unable to succeed due to massive inequality and needing to just survive day to day will have their time freed to apply themselves to doing something great.

Having economic value is not the only way for human contributions to matter. Not even close. He's an artist and perhaps should know this.

It doesn't logically, intuitively, epistemically-rationally, or operationally necessarily follow from UBI that people no longer have value or the ability to aspire. Why does he assume that all of human value is tied to their economic worth in the strict, ultra-doctrinaire, capitalist sense?