At least with RISC-V you can always synthesize the core yourself in an fpga. It's vastly easier than it used to be and cheap fpga boards are becoming quite powerful. Something like the upduino board has a low barrier to entry. I'm particularly excited by the artix-7 line which also has open source toolchain support, though i haven't tried it myself yet.

Putting it in an fpga isn't as efficient as using the same area of silicon to make an asic, but for alot of applications it's totally fine. Plus you can actually hack on the architecture to suit your needs. An open and adaptable computing fabric that can be synthesized on demand sounds pretty disruptive to me.