I don't know about "easily" but let's assume sure, who would you even consider doing it? The biggest non-"reference" CPU core design is Apple's, and Apple is an

I don't know about "easily" but let's assume sure, who would you even consider doing it? The biggest non-"reference" CPU core design is Apple's, and Apple is an ARM ISA founder so why would they care about switching to RISC-V? For others, like Qualcomm, Samsung, or Amazon, they are licensing the ARM-designed CPU cores not designing their own in-house. So they wouldn't be able to switch those to RISC-V, it's not their IP.