I often wonder what kind of stack websites that fall over under HN traffic have.

From my perspective HN doesn't actually bring that much traffic, so I find it curious which software is so fragile to fall over when getting HN front page traffic.

Before you have that need it seems like premature optimization. If I had a blog that was getting a handful of views/day, I probably wouldn't bother with CDN/scalability until it became an issue. Or use something like Medium (which I do).

Yeah, I've always thought blogs that didn't render to static pages were just sorta silly - for just a few hits a day, it's very simple, and if you get a flood of traffic, even a small vps could keep up.