This is all fantasy. PG runs this in his spare time off a single server. Every feature I saw on the list has viable workarounds. Yes, it'd be nice if they were supported out of the box. But I don't think the lack of native features is negatively impacting the content of HN, which is the most important part.

So what's the argument of the site? "Hey PG, we know you're busy funding startups and stuff, but we're mildly inconvenienced by some UX decisions you've made with that experimental site you run on the side, and were hoping that you could take the time to implement these seemingly-minor features that've been discussed on HN for years. In exchange our happiness while using the site will be somewhat increased, and we will instead whine about HN's lack of modern CSS and Twitter Bootstrappiness and what have you."?