You outline only a single solution of which there are many. The thing RISC-V gets you is the ability to iterate on an implementation while still running the body of existing code. As ridiculous as it seems, this hasn't been possible before. RISC-V didn't technically need to exist but it did politically and legally.

I don't think your equation is fact or rigorous, I respect your work but it call bull on it. And there are way more than 3 options, this is a false dichotomy.