This is true, you don't need blockchains to share revenue. Whatever account is getting the revenue can just share amongst contributors in some pre-arranged way. I just think smart contracts present an interesting way to automate that work.
As you're saying this might not be the best way to think about it. I'm a big fan of open-source and license-free assets. I think both of these concepts have a place. For some things, a creator will want free and open use of an asset, just adding value to the community, for some things a creator might do custom music for a game project and want to get a reliable cut of the pie moving forward. It all depends.