RISC-V is not a ISA, but a family of ISAs. That is why is has a small core and plenty of extensions. So instead of having a dozen completely different ISAs you

RISC-V is not a ISA, but a family of ISAs. That is why is has a small core and plenty of extensions. So instead of having a dozen completely different ISAs you now have a dozen almost the same ISAs. It was meant to be forked and customized for needs. Ideally, your needs can be met by selecting from the basket of already ratified extensions. So what if no one else has the exact set of extensions you do? A lot easier to support if you share a common core with already supported chips. Look at how many programming languages look C and how much easier it is to pick them up than say APL. Think of Risc-V as the C of the future.