Extremely unlikely. The beauty about RISC-V is that it's open source and royalty free. Both arguments aren't that relevant for Apple, as they got an architectural license from ARM which gives them full access to everything and allows them to design their own chips and because the royalty charges are vanishingly small compared to the prices Apple charges for it's products.
Apple has also already invested so much effort in its own ARM chips that I believe it wouldn't make much sense for them to throw that away in favor of RISC-V, just for saving a few million dollars per year in royalties.
> Extremely unlikely. The beauty about RISC-V is that it's open source and royalty free
The other beauty is that you can extend the ISA with whatever proprietary instructions you want. Others develop 99% of the ISA for you, and you focus on the 1% that differentiates your product.
I'm not sure if the ARM licenses allows them to extend the ISA with "Apple-only" instructions, but RISC-V does and it allows Apple for more vendor lock-in. E.g. you can't use a Hackintosh anymore without buying a CPU directly from Apple.
I think Apple could stop Hackintoshing on Intel (in a practical sense) if they really cared to do so. There will always be the extreme fringe who would get it to work, but it's so easy at the moment to get a fully functioning Hackintosh (including iCloud, iMessage, App Store, etc) that I have to believe Apple is both aware and doesn't care to try to stop it.
Apple has also already invested so much effort in its own ARM chips that I believe it wouldn't make much sense for them to throw that away in favor of RISC-V, just for saving a few million dollars per year in royalties.