I disagree. A lot of HN's character and culture are a result of how unmodern/unconventional it is.
For example, not being able to get reply updates by email means you have to come back to the site to check, for example. Is that good or bad? I don't know the answer, but it selects a different audience. A modern HN would be a different HN community and culture.
However, that still makes it a conscious choice to engage with the service that way - the default way is still checking back, and that shapes the general usage patterns of the site, even if some people have concluded it benefits them more to modify their experience.
For example, not being able to get reply updates by email means you have to come back to the site to check, for example. Is that good or bad? I don't know the answer, but it selects a different audience. A modern HN would be a different HN community and culture.