open platform developed and produced by different defense companies

how to get weapons program spending under control, 

make every weapon system an open platform that every defense company could develop and produce, 

whether defense companies are national or allied, 

if weapon system development become too expensive, 

then just switch to other defense company, 

if weapon system production become too expensive, 

then just switch to other defense company, 

this system will make it possible for politicians, bureaucrats and companies to continue with games and intrigue 

this system will become more relevant when defense industry become more automated and start using different types of 3d printing large scale