I wouldn't say it is a small corner. One of the example I added was for Esperanto Technologies.
The small ISA allows them to make tiny specialized vector processing coprocessor which they can fill up an ISA with.
Their ET-SoC-1 has over 1000 RISC-V specialized cores for vector processing, using the RISC-V vector extension.
Future SoCs will increasingly use more coprocessors. And these coprocessors as ET-SoC-1 shows, have a high chance of being RISC-V based.
As for the other aspects you mention, I cannot claim to know much about that. However we know that breakthroughs in fundamental problems like that tend to happen in Universities. And what processor are universities primarily using in their research? Well, RISC-V of course.
Hence I think we are going to see a lot of important innovation in the future happening in the context of RISC-V designs.