If Apple cares about their chip IPs, it will be very hard to trust Intel given Intel's past behavior with others like AMD.
The modern Cortex and Infiniverse designs are so pathetic that RISC-V might mature by the time ARM is the industry standard. And the smaller ARM IP hasn't been profitable since China mass-produced the clones. Courting Intel into buying an architectural license with a free IP bonus is a legitimately smart move for ARM's longevity, from Apple's POV.