Unix Shell Programming: The Next 50 Years – HotOS Xviii [pdf]
sigops.org
sigops.org
Concerning Powershell the author of oilshell addresses how shells are native to their surroundings in http://www.oilshell.org/blog/2021/01/philosophy-design.html#... - he'll be attending the HotOS panel too. Implementing WSL2, native openssh in Windows, the use of bash, it must be to stay relevant.
Edit: and I think this thread will interest you too - https://lobste.rs/s/k10sfa/why_did_i_write_my_programming_pr... and the sustrik/uxy reference within
What I would like to see is PowerShell becoming default in more and more distros. The only problem to achieve that is today making its performance better.