They sold all of the ARM shares in mid 90s to prevent themselves from going bankruptcy.

Not to mention starting a JV has nothing to do with perpetual IP access. You will still have to pay for it.

They can certainly have a contract with Arm that allows them to renew their arch license in perpetuity that nvidia won't be able to void.

I obviously don't know that for sure but the idea that Apple would stake their future on something they don't have a legal ironclad position seems unlikely.