It's case of https://en.wikipedia.org/wiki/Metonymy. Silicon Valley is no longer just a physical place, but also represents the tech industry itself in popular imagination. Also, while the article is centered on Microsoft, I think the title is meant to be general, as shown by this passage:

> The project represents a much wider effort to build a new breed of computing system that is truly conversational. At companies like Facebook, Amazon, and Salesforce as well as Microsoft...

"Silicon Valley" has unfortunately become clickbait. We replaced the title with a representative sentence from the article.

Microsoft is still in grunge-town?