For me, the big problem in your post is the "996 culture". That means the expectation is that everyone is pushing forward with a similar intensity. Now, perhaps you were talking specifically about individual efforts given your examples of artist and self-employed, but when I think about culture, I think about groups of people, and in that context 996 is problematic.
It only provides work-life balance if there is not much of a "life" to balance, where taking a break once in a while is fulfilling enough. Maaaaaybe this can work in your early 20s, but it basically removes anyone with kids, hobbies, outside interests and responsibilities, and really, anyone with life experience out of the equation. It is a highly exploitative culture, sold under the guise of camaraderie, when anyone who has gone through one or more hype cycles can tell that the majority of these startups will fold with nothing to show for them other than overworked, cynical individuals and another level of normalization of exploitative practices.