The dollar value of winning a military procurement contract is incredible and putting a contract out for a highly visible defense item incredibly troublesome. It is all due to profit. You can look at the Air Force KC 46 tanker contract award.
http://en.wikipedia.org/wiki/Boeing_KC-46. The contract award started in 2003 and was delayed by procurement fraud, corruption, congressional meddling, and it was not until 2011 that a contract was finally awarded . Who wants to go through that? There is so much profit to be made by military vendors. The winning vendor gets a monopoly on parts, maintenance, supply, and big, big profits in foreign military sales.
The Program Manager who led the M92 pistol through downselect came and briefed our Gun Club a couple of years ago. It was a "process" orientated briefing and it was a very good learning experience on how to conduct a downselect between contending designs in such a political environment. The procurement for a new Army pistol was horribly politicized at the time with Corporations using their Congressional sock puppets to delay, frustrate, steer, the procurement process.
The Army has not forgot and whatever good new designs are out there, they are not so much better than the Beretta for the Army to go through the travails of buying a new pistol.