Indeed, I joined 9 days after you (and have within 1% of your karma (!)), and my experience is the same. HN was founded with a keen awareness of how online forums tend to go downhill over time, and there are specific rules to avoid it.
But IMHO, the saving grace is the fact that HN is not built to grow. Growth is what ruins every online community. There are still plenty of small communities have have been going fine for years or even decades because they didn't experience explosive growth. As soon as you have something like Twitter with massive investment and market expectations, you know the community is done for. To Twitter's credit though, the mechanic of following individuals does scale much better than a forum though. Subreddits were also a good idea that allows some community while scaling. But in both those cases it works because they create sub-divided communities rather than one massive one which inevitably breaks down.
I'm wondering how many similarities your comment also has to do with capitalism...
Some areas of business make a good local idea, regional idea, but VC firms want you to expand and swallow the world. Maybe that's also the wrong way to think about it: maybe coexisting in the local economy is a better, more stable, and amicable way to go.
But IMHO, the saving grace is the fact that HN is not built to grow. Growth is what ruins every online community. There are still plenty of small communities have have been going fine for years or even decades because they didn't experience explosive growth. As soon as you have something like Twitter with massive investment and market expectations, you know the community is done for. To Twitter's credit though, the mechanic of following individuals does scale much better than a forum though. Subreddits were also a good idea that allows some community while scaling. But in both those cases it works because they create sub-divided communities rather than one massive one which inevitably breaks down.