Perhaps the most important contribution Linux has made to the world is that because of its impact, you can run an OS on nearly any instruction set architecture (ISA). That drops a pretty huge barrier in terms of getting to something from nothing. On RISC-V though, unless it was some sort of SoC (which most people won't build) I don't see the impact. But carrying that line a bit further ...
One of the challenges that Microchip has faced was that the affinity for C that the ATMega architecture had from rival Atmel meant it lost a few significant design wins (Arduino perhaps the most serious). They could use RISC-V to try to offset the Atmel SAM series. But other than that I don't see the motivation for folks to not use ARM, granted a full processor license would be expensive but if you are looking at volumes where that would be an advantage, it isn't that expensive.
One of the challenges that Microchip has faced was that the affinity for C that the ATMega architecture had from rival Atmel meant it lost a few significant design wins (Arduino perhaps the most serious). They could use RISC-V to try to offset the Atmel SAM series. But other than that I don't see the motivation for folks to not use ARM, granted a full processor license would be expensive but if you are looking at volumes where that would be an advantage, it isn't that expensive.