Then what are acting and music royalties?

They're the exceptions that prove the rule. For every Taylor Swift, there are probably tens of thousands of songwriters who have never earned a dollar from their creations.

The vast majority of valuable copyrighted/patented creations are works for hire, which is compensated just like other labor. Or the creator signs or licenses the rights away to a publisher and maybe receives contractual royalties, rarely more than the initial advance.

(An alternative answer is "the pay for your creativity is a capital asset. That asset can earn royalties. Usually it doesn't.")