"you" as in person with required skills, resources and access to a chip fabrication facility. For many others they can just buy something designed and produced by others, or play around a bit on FPGAs.
We will also see how much variation with RISC-V will actually happen, because if every processor is a unique piece of engineering, it is really hard to write software, that works on every one.
Even with ARM there are arguable too many designs out there, which currently take a lot of effort to integrate.