[timschmidt]

Lack of funding is not among the top reasons the US space program never produced a reusable rocket. The US space program, like most nation state space programs, is organized as much to keep weapons developers employed as to build rockets. It was the reason we cooperated with Russia on the ISS. As such, the projects get split and sub-contracted to many different suppliers in ways which prevent the sort of top-down integrated whole-systems engineering required for reusability. Changes to make one part more reusable necessitate changes in other parts of the vehicle, and the moment those cross systems boundaries that span different organizations, you're screwed.