You're mixing implementations and the ISA. A RISC-V chip can be as daunting as any other x86 and I can assure you they will be. Those modes are one of the ways

You're mixing implementations and the ISA. A RISC-V chip can be as daunting as any other x86 and I can assure you they will be. Those modes are one of the ways to enforce export controls. Any competitive chip has something similar, say ARM TrustZone or whatever x86 manufacturers name their security mode. If you don't put such features, the Asian manufacturers will instantly copy your IC.