The credibility point is the most interesting part of this. In semiconductors, having a good design seems secondary to convincing customers that you'll still be around to support it years later. RISC-V lowers the barrier to building a CPU, but i'm not sure it lowers the trust barrier nearly as much.
I'm not so sure of that. Don't companies often buy a million of a chip and then that's it? Famously the MacBook Neo was created to get rid of some stockpile of old chips Apple was sitting on.