The rationale is that the value provided by fixing the problems is less than the cost of doing the work.

This particular problem isn't going to cause tons of people to leave, and fixing it isn't going to cause tons of people to join.

Unless someone does the work for free, or manages to get a large portion of the current users to quit over the issue, there's no reason to expect it to be changed.

Actually we change things almost daily.

Any recent examples? (Just curious, not trying to debate you)

I'd guess it'd be under the hood tweaks related to building and maintaining the community (comments and stories)

Right now the top priority is moving to a new server.

Can you explain where I got this impression, or am I completely out in left field?

You're probably judging from the site's appearance, which doesn't change much.

I'm assuming the minimalism and hackish nature was deliberately chosen to weed out the lowest common denominator and cater only to the niche HN targets.

That can't be right? Last time I heard they were all about inclusion by being a gateway.