One of the problems is "turbulence" in the many programs the Army and the other services have. Some of the turbulence is due to a painful shortage of funds in the R&D accounts. Lower level leaders rob Peter to pay Paul, which makes Peter take longer and cost more in the long run, requiring someone else be robbed to pay Peter. Their leadership, aided and abbetted by Congressmen seeing only pork, rather than programs vital to the nations security, don't make the hard decisions to canceling Peter and using his resources to make Paul healthy.
Thus, the whole system just sort of shakes, and nothing gets done well or even close to on time. Plus of course internal politics sometimes cancel and scrap a legacy system, *before* it's replacement is ready. Which really messes things up.
Thanks for the more informed and detailed description of the processes involved, and I also believe that their are treasonous culprits involved at higher levels (DOD, STATE, and Congressional) too.