Comment by vidarh

You're making the unsubstantiated assumption that the job will replace the time spent on their art rather than replace the time spent trying to sell their art.

Since most peoples art sell extremely poorly, it's entirely plausible for most artists to replace their income by replacing their sales effort with another job.

For a tiny sliver of the highest paid artists, it might have an effect. In a lot of markets this is already addressed by public funding and patronage because even for many of they highest paid it is hard to make a living from sales.