I also assume that you get very minimal or nil traffc to those pages.
That's a reasonable assumption. Either that or they don't earn income.
If it's an issue of traffic, could it be a matter of how the hub structure was initially set up? The following is a simplification to illustrate the concept. The point I'm trying to make is that it's important to break apart the site into segments and build links to the uppper segements and the sub-segments. If necessary, create sub-sub-segments and build links down to those. The idea is to create a structure that is friendly toward building links to the increasingly specific hubs.
Red Widgets - 1,000 pages
Orange Widgets - 1,000 pages
Yellow Widgets - 1,000 pages
Green Widgets - 1,000 pages
Blue Widgets - 1,000 pages
The above structure creates a situation that limits the ability to build links to five hubs: Red, Orange, Yellow, Green, and Blue. The link juice trickles down from there (plus the home page and scattered pages). The above structure makes sense when a site is smaller as well as for presenting the least amount of choices for a site visitor. But as a site grows it may reach a point when it becomes important to construct a new taxonomy, creating finer classifications.
This means treating each hub/section (or in this case, color) as a separate website and building the architecture as if each section were it's own mini-site. Then build links to each of the hubs, with the primary color being the main hub, and the sub-sections being mini-hubs to which you can build more links to.
Red Widgets
Red A widgets - 200
Red B Widgets - 200
Red C Widgets - 200
Red D Widgets - 200
Red E Widgets - 200
Orange Widgets
Orange A widgets - 200
Orange B Widgets - 200
Orange C Widgets - 200
Orange D Widgets - 200
Orange E Widgets - 200
Yellow Widgets
Yellow A widgets - 200
Yellow B Widgets - 200
Yellow C Widgets - 200
Yellow D Widgets - 200
Yellow E Widgets - 200
Green Widgets
Green A widgets - 200
Green B Widgets - 200
Green C Widgets - 200
Green D Widgets - 200
Green E Widgets - 200
Blue Widgets
Blue A widgets - 200
Blue B Widgets - 200
Blue C Widgets - 200
Blue D Widgets - 200
Blue E Widgets - 200
The above site structure creates the opportunity to build links to thirty hubs. That's like having thirty websites working for you. Only instead of being thirty sites working independently, they're working together.
The distribution of PageRank is more precise, focused, and efficient. The home page PageRank might be lower but the longtail ranking ability and the shorter keyword ranking ability should be increased. As one of my sites increases I think about how I can segment it into smaller hubs. At a certain point there are enough pages to support a distinct hub. That's when I split a section and create a new hub. It works for the site visitor because it makes finding information easier and it works for link building and ranking, too. Often, what interests people can generally be drilled down to a more narrow niche focus.
So for the case of Red Widgets, you bring links to the Master Hub, Red Widgets. But then bring links to the sub-sections, A, B, C, D, and E. All the red sub-sections must interlink to each of the other Red sub-sections, as well as to the Master Hub (Red Widgets). All pages throughout the site feature a link to the other Master Hubs, the home page, plus other ancilliary pages (about, contact, etc.).