*I am probably more with you than against you, ultimately*
"I don't make money off code I wrote 10 years ago - it's absurd that an artist would expect the same."
You would be if you had written and were selling the final product yourself. But something you wrote for your employer? Probably not. Likewise, an artist (maybe a scientific illustrator, for example) who produced art and was paid a salary to do so, probably isn't making any money off of it now.