Just because custom art is easy to distribute after its finished, someone still needs to spend hours if not days making it.
This question shows a strong lack of understanding for the logistics of custom art. Custom is the key word here, because it has to be created in the first place before you can copy it. When you commission a piece you’re paying for it to be created in the first place.
Drawing as a job is stressful and tedious, it’s not the same as drawing for fun on occasion. It requires hours of attention, electricity, years of training, and man hours that could be going towards more fruitful labor. Just because you can copy-paste the end product, doesn’t mean you have the resources or ability to create custom art.
TL,DR: If you can’t do something yourself, don’t underestimate the process required for doing it.