I am sure that if and when Toyota decides the 1 ton market is viable you will come up with something like, " Uh the F550 can do this..."
So you are saying that half ton trucks are no longer real trucks just so I understand you correctly?
Sure that's your opinion or may be your minimum required needs for a truck and that's fine. Putting up a diesel engine that is only installed on 3/4 ton and larger frames and comparing it to a half ton power train is not what I would call a logical comparison.
If you need a truck with those specs then certainly the Cummings powered Dodge, a older power stroke such a 2002 (not thrilled with the newer motor myself as I drive both power strokes at work but my primary truck is a 1 ton 2002 power stroke) or the Chevy Duramax are good selections.
I will also admit that half ton trucks are not fit for my workplace, they are two light and they get beat up by the roads and have multiple parts failing all the time (we have dual fuel CNG/Gas f150's in the fleet). The one tones are needed just to handle the rough roads and the deep snow.
So if you want to say that fort many applications a half ton truck is not adequate then I will agree with you.
But for many businesses and people a half ton truck fits the bill. Landscapers, independent tradesmen, carpenters, electricians and plumbers have gotten by for years with half ton trucks and vans. For the family that wants to pack a light picnic trailer or the boat owner who likes to make impromptu dashes to the boat ramp when the weather permits, the half ton trucks has served and continues to serve that niche. It is still a real truck, it is simply lighter duty than heavier rated trucks obviously.
For that extra capability the market dictates a premium price. That towing ability , diesel engine and heavier axles do not come cheap. At work I drive a Super duty, the diesel engine and heavier frame take a beating but it does still break down from time to time with small stuff that still leaves me literally out in the cold when the engine won't run. Cam positioning sensor, bad injectors and a couple of torque converters have failed on my work truck. But I also have dusty summers and winter temperatures that are inhumane.
At home all I need is a light truck. A super duty would be overkill. A half ton is overkill. So my Fake truck Tacoma and I haul 5k lb trailers and fill the bed with Compost to take care of my needs and go play. When I am driving around unloaded more than half the time at home I sure am glad I don't have a 1 ton.