RISC-V is just an instruction set specification. It says absolutely nothing about the peripherals that need to be attached to a RISC-V core to produce a usable

RISC-V is just an instruction set specification. It says absolutely nothing about the peripherals that need to be attached to a RISC-V core to produce a usable system. Whereas the IBM PC was delivered as a complete system (including all the peripherals and glue logic) and to achieve 100% compatibility the clones were exactly that: they copied absolutely everything about the PC, down to level of the individual logic gates in the "glue" that interfaced the CPU and memory and peripheral controllers.