Two issues:
1. The military was ALREADY IN THE PROCESS of buying the new variety of body armor when the war broke out. Everyone DID have body armor...just not the new variety. As soon as the overwhelming superiority of the new was recognized, a crash program to buy the new was implemented....but...it was dependent on the speed with which the company that made it could respond. New equipment is fielded according to a fielding schedule. It is also true that it took time to field the M1 Abrahms to every armor unit when it first came out. It was a vastly superior weapons system. Many had the M60 for many years while the Abrahms was being fielded. Did that mean that the military valued them any less? No. It meant that there was a fielding schedule and budget established by Congress.
2. Kerry voted AGAINST the money to buy the new body armor.