When regular commissioners stop being cheapskates.
Thing is though, if two people came to you with art, you liked both styles equally, but one of them was cheaper, which would you go for? It's not 'being cheap' to pay a lower price for the same quality of service, it's good business sense. Not that I'm saying it's ALL the artists' fault for charging too low. Goodness me, no! The fault lies on both sides of the divide. People who pop up offering $1 for artists to draw for them are the ones being cheap. I mean come on! I'm on the freakin' DOLE here and I can afford to save up $20 if I really want an image making. If you've really, genuinely only got $1 to spend, you shouldn't be spending it on art! But commissioners' attitudes aren't likely to change if the status quo lies in their favour, are they? If someone says 'I want this for $1' and five people pop up saying 'Ok! I don't need to eat today!' where's their motivation to offer more? At $1 an image I could illustrate a whole book on a $50 budget, but I don't because I respect the artist's skill.
I don't tend to do commissions these days because to be frank, the kind of art I do, it's just too time-consuming. A good quality 3D model takes eight hours or more to get right, when everything that goes into it is considered. If people won't even pay $10 for something, they're not going to get near the $100 or so that I'd have to charge to make it worth my while.
Not that I'm saying other types of art take especially less time. I know a lot of artists in many genres and styles, so I know the work and effort that goes into a good image. That's just the position I'm in personally, using a pay scale based upon the (local) National Minimum Wage. And as others have quite rightly said, good artists shouldn't be getting minimum wage. Also, with 3D, I can't downscale my output to match a budget. In other words, the time difference between making a colour image, a greyscale image and a black-and-white image is practically nil.