The overwhelming majority of people of any income level will never pay to commission any kind of art or even be familiar with the possibility to consider as a practical option.

It's just not a typical thing to do pre or post AI. "Revealed preference" doesn't seem like a useful lens without some basic degree of awareness that a choice even exists.

And on the flip side, I have a friend who commissioned some kind of avatar for social media from an artist friend of friend for the first time in their life. They loved the result a lot and since then have commissioned a bunch of little random things once they realized it was a thing anyone could easily do with a few bucks. For stuff like their WoW character/guild, D&D, social media, etc.

They make less than six figures, each request was <$100 IIRC. Budgeted basically like any other gaming/hobby purchase for personal entertainment.