I've seen some people ask "Why do artists charge more for complex characters?" and I'm here to explain this for you.
Are you ready?

Because it takes more time.

That's it.
It's not personal. It's not a conspiracy. It's not something "only furry artists do".

As an example, take an artist who really likes drawing wolves and has a lot of experience drawing them; they can draw a wolf character start to finish in 2 hours and they charge $20 for it. Then someone asks them to draw a six-legged cotton-candy ostrich with 5 dragon heads, each wearing a richly decorated crown that glows with a divine light. That's going to take longer, a lot longer. If you're used to an hourly rate of $10, it doesn't make sense to charge $20 for a job that might take 12 hours. They'll either charge $120, or decline the 6-legged-king-candy-dragonostrich commission and take 6 wolf commissions.

Because illustrators are freelancers and they have bills to pay. Like a carpenter or a roofer.
A carpenter will charge more for building a bookcase than he will for hanging a shelf.
A roofer charges more for a roof than they do patching a leak.
It's a matter of time and materials, and yes, digital art also requires artists to update hard- and software; those count as materials. Contrary to popular misconception, digital art supplies are not infinite. Sooner or later your video card, monitor or Wacom will break down and needs replacing.

I know modern society, say post 1700's, has tried to elevate artists from artisans (such as carpenters and basket weavers, craftspeople) to something more akin how ancient Greeks viewed artists, as recipients and conductors of a divine inspiration, who transmute and translate the unknowable into sculptures, paintings, poetry that "normal mortals" can enjoy.

In my experience, "unknowable" is all too often equated with "worthless", so if it's all the same to you, I prefer to be treated like a carpenter or a plumber.

Not on a pedestal, but also not expected to work for free.
(At least not to the extent artists are expected to work for free.)