A few years ago there was a Concord
brand, like Sunseeker, that was sold by Forest River
not Coachmen. It didn't sell very well so it was folded and the GTS Series was created.
I think part of the problem is the GTS series is priced relatively high and dealers seldom carried one as part of their stock. I can understand that as the GTS design makes it a niche market unit. Most dealers won't carry a "Trekker" cap in their inventory for the same "niche" market reason.
I suspect that since the "Trekker" option allows several floor plans to have the GTS "style" that it's marketing's replacement for the GTS line up. Especially since the Trekker is a "No Cost" option when ordering.
It will be interesting to see what, if anything, FR does next. Bringing out a Ford F-450 based replacement would get me looking...