In the beginning, the main commercial interest in RISC-V, is as an internal MCU core which is not customer-programmable. In my previous job, we used an OpenRISC core, and it was awful. If I didn't quit I would have made a very strange push for developing a simple RISC-V core, at least once the compressed ISA was finalized.

It's very simple to make a small and efficient RISC-V core in-house, and if that means we can avoid paying a huge amount of money to ARM, that's fantastic. For some products (radio microcontrollers), it's possible that RISC-V will live alongside ARM for a while. Maybe if RISC-V is lucky, semiconductor companies will start to allow customers to program the RISC-V core, and that creates an opening to take on ARM. All it takes is one big customer that says "we are willing to take the hit in debugging and development tooling, in order to save a few cents in ARM licenses on this chip"

You can kind of see ARM positioning themselves for this reality as well. They are branching out into a lot of different areas in order to stay relevant. They've invested massively in debugging IPs and are now investing in architectures for more secure CPUs/MCUs (TrustZone). They have GPU cores, DSP extensions, etc.

Over time, the market for "plain, dumb 32-bit MCU cores" will definitely be taken over by some open source, royalty free solution.