The good RISC-V designs are not free though and the free ones are not good. MCUs are not a category of computer to draw lessons from for the broader market.
The good ARM designs aren't free either. The big difference is that you'll always be stuck paying Arm (either for whole ARM cores, or a licensing fee for your own design), whereas with RISC-V there can be genuine competition between companies offering performant RISC-V IP.
In the MCU market the compute core is already an off-the-shelf drop-in component. Just look at the RP2350: in addition to its traditional ARM cores they also last-minute dropped in two RISC-V cores because it was so trivial to do - and you can select which set is active via a boot-time firmware flag. I very much doubt we'll see that kind of flexibility with high-end client compute, but with the switch to separate compute chiplets we're not far off already!
iirc Christenson's chief example was IBM not deigning to cannibalize their high-end disk drive business by competing on the new, less capable low-end devices.
In the MCU market the compute core is already an off-the-shelf drop-in component. Just look at the RP2350: in addition to its traditional ARM cores they also last-minute dropped in two RISC-V cores because it was so trivial to do - and you can select which set is active via a boot-time firmware flag. I very much doubt we'll see that kind of flexibility with high-end client compute, but with the switch to separate compute chiplets we're not far off already!