It is my understanding that the original jeep was a BANTAM, not Ford, and the US army was afraid it (Bantam) was too small of a company to supply the demand. The cantract, for that reason was given to both Willys-Overland and Ford to build the military vehicle, (not yet named Jeep). Ford became instrumanetal in the manufacture of other vehicles during the war and Willys-Overland emerged after the war as the sole manufacturer of military and civilian Jeeps until bought by Kaiser in 1951 (may be wrong on yr) when it became Willys motor co. , later Kaiser-Willys, later Kaiser Jeep, American Motors Jeep, then Chrysler Jeep.
The Humvee was a joint venture of two companies, American Motors and General Motors= AM General. AM 's part was bought out by GM. The original military version used the GM 6.2L diesel motors. They went into civilian manufacture as a GM company with the 350 (5.7L) gas or Gm diesel as the Hummer H1.
The concept of the Jeep and the BASIC design is the same, albeit modernised and updated. And has been with us for over 60 yrs. But the Hummer could not weather the storms that Jeep has survived. My question, more or less is what do you think the differences were that caused Jeep to be sold like a cheap mule over and over to survive while Hummer took the dive like Edsel, Studebaker, Packard and the like?