I remember in the very early days of ZeroTier him stopping by our tiny coworking office in SoCal (we weren't scattered all over yet). He said it piqued his interest because it was "something that should have been built 10 or 15 years ago." (I'm paraphrasing. This was around 2015.)
He belongs to the old Silicon Valley. I wasn't there in those days and have never lived there, but I miss it.
It was back when SV was genuinely creative and largely positive in its attitude toward people and the future. It emerged from the ethos of places like SRI's "augmented human intelligence" lab and things like the Whole Earth Catalog and the Homebrew Computer Club.
Of course I'm well aware of the other origin story, the one that goes back to WWII and the defense industry. They're both true in different ways, but I think the ideas I mentioned above were the ones that came to dominate for a while.
I'd say until the mid-late 2000s.
I have this goofy speculation that the old Silicon Valley more or less went bankrupt in the dot.com crash in 2001. After that it was bought out and taken over by different interests with different goals. Probably bullshit, but it'd make a good novel plot or something.