That HN comment may have a historical significance you can't see now, but it will be lost because of automatic copyright. The most valuable historical material

That HN comment may have a historical significance you can't see now, but it will be lost because of automatic copyright. The most valuable historical material are the thoughts and experiences of "average people", because that's how we can truly understand an era. How will people in 500 years understand this era when it is likely that most of the popular culture and social commentary will be lost by then?