You’re missing, somewhat gleefully, most of the history of western art, which you could imagine as split between patronage-based art (have you heard of the Sistine Chapel, for instance?) and vernacular art - where things like genre storytelling and family portraits come from.
Broadly speaking, vernacular artists work for a fucking living; it’s rare there (like in most pursuits) to get super rich. We can’t all be David Baldacci or Danielle Steele.
NB: Thanks to Neal Stephenson for the best essay on this. He calls genre artists “Beowulf” artists.