> are any companies other than Nvidia embarking up AI/ML chipmaking in a closed fashion?

https://www.cadence.com/en_US/home/solutions/machine-learnin...

https://www.synopsys.com/implementation-and-signoff/ml-ai-de...

https://www.plm.automation.siemens.com/global/en/our-story/n...

I think you'll be hard pressed to find any company using open source tools to design a business-critical chip for a foundry that gives any information without an NDA.

AFAIK Google doesn't have a open-source ASIC design for OpenTitan, and WD doesn't have an open-source ASIC design for SweRV.

there are a lot of interesting initiatives, but in the semiconductor industry open source tooling and processes are only a tiny niche that a few companies are playing around with.