Why is US Army unble to replace the M2 Bradley?

The M2 Bradley entered service in the U.S. Army in 1981 and were intended to transport up to seven soldiers into battle. Both M2 Bradley infantry fighting vehicle and M3 Bradley cavalry fighting vehicle are named after General Omar Bradley known for saying, “Ours is a world of nuclear giants and ethical infants. We know more about war than about peace, more about killing than we know about living.”