I wonder why Voyager never made any use of the Iconian storyline. They could have made an episode arc where they are in a region with lots of Iconian ruins and remnants, and eventually fight about one of those portals.
But they (TPTB) would have fucked it up and VOY would have just gone back to EARTH. When they could have gone back to something at least remotely sci fi interesting, like some Borg civil war we never heard of or the Talaxian Bronze Age. But no, it would have been all hoop skirts and other such nonsense in Janeway's Indiana of yore.