I think the mono-conversation group is present on HN, but I feel like it's balanced out by a pretty substantial group of people who have made a conscious decision to live somewhere other than SF or NYC because they don't agree with the culture.

Every once and a while I see a comment deriding the ability of people who live outside of silicon valley to make a meaningful impact on the world, and it is heavily downvoted without fail.

I think that's a good thing personally, because HN would suck if it was merely a SV echo chamber.