Not really. At the end of the day they are both products that mostly require knowledge and manpower. The ability to easily replicate the computer made thing does mean you can spread those hours over more people (therefore charging 5$ for a mod, instead of the at the very least hundreds you'd pay for a painting.) You could argue the same thing against charging for video games, or any software. Only involves knowledge and man hours but no raw materials, and with digital distribution they never take any form for you other than 0s and 1s.