Can you establish whether they are less viewed because of less demand (despite ranking just fine), or because, despite plenty of demand, you only get the dedicated searcher who gets to page 23?
A mixture I suppose.
Some are just old news items which used to be linked to from the home page. As they got older they are only linked to from an archive page and whatever other cross-links from relevant pages.
I would guess that most of them never ranked particularly well as they were fairly well covered stories on other sites that we simply can't compete with. Even if they had a unique angle then, they don't anymore. I probably won't put too much effort into most of these.
Other pages may be more unique in their content, but are still perhaps a spin on fairly common subjects – blog-style opinion pieces, or tips about a technical subject. It's these that I suspect it might be worth the most effort to try and pick up long-tail searches?