Colorado legislation, for example, won’t change if the OS license changes.
Considering macOS is already built on an OSS kernel (Darwin), and that Apple no longer charges any money for OS upgrades, I could imagine a world where Apple just shuffles some components around and announces macOS is now fully open source. Just so happens to require a lot of Apple chips with proprietary firmware, but hey that's for security reasons. Trusted enclave and all that. Nothing to see here. We'll take the exemptions for FOSS now please.
(Of course the real reason Apple won't do this is that they already have almost all of their user's ages via Apple ID, and being a trusted age-auth intermediary actually plays to their core strengths really well.)