Which companies in SF Bay Area are still developing using Spring Boot/Java tech stack in production for any recent or newly launched services? Or is everyone only using Python or Golang or something other than Java?
Enterprises use it for new services often, at least here in the UK. Java generally isn't the best language for young disruptive companies though which might be why you don't see hot SF bay area companies choosing Spring Boot.
Node, Golang, and Python all seem popular depending on what you're building...
I haven't seen it since 2015.
You may wanna hop on to LinkedIn and do a quick search for the jobs demanding the specific technologies you wanna know usage of. That is not the ideal way, but should be a good estimate anyway.