Almost missed that this was you KW, since you changed your avvy lol.
Good analysis and I can tell you I feel very similarly. If we're custom ordering trucks, it's probably because we're more discerning (picky) that your average truck buyer (who are already pickier than your average vehicle buyer). And from my own research, I agree that if you custom order a Ford or a GMC, and tweak it to your liking, it's gonna cost you (lot prices are a bit closer). And there wasn't anything about those trucks that was enough to pull me away from Ram.
I mean, I really like the GMC tailgate, and Ford's better-than-average payload and the in-bed generator, that stuff is neat. But you gotta pay for it, and it's not worth it to me over the Ram's air sus and ride comfort, the interior design and overall quality, the screen (I LOVE that it's vertical, the screens that are long horizontally makes no sense to me, it's putting stuff on the right side of the screen father away from you). Trucks have been targeted for a long time toward people who use them to tow and haul stuff regularly, but also like to just drive them around town when needed. Ram has latched onto a fairly specific but surprisingly broad customer base of people looking for a truck to drive around everywhere, everyday, that can also tow and haul stuff when you need it to.
My wife and I test drove a Sierra Denali with the 6.2. Rode/drove/steered like a truck. Then we test drove an F150 (Lariat ecoboost). Smoother than the Sierra, but still, you know you're in a truck. Test drove the Ram (Limited) and it was like night and day. We knew instantly Ram was the way to go. So, definitely giving up some payload and power vs the other two, but it all depends on what you're gonna use your truck for. At the end of the day, this is my daily driver so between that fact and the better prices on Ram, it was an easy choice.