The Cobra first came online with the Army in Vietnam in 66-67, the twin engine versions about 4-5 years later. It amazes me how many weapon sysyems the US still has that was in use when I was got out of the Army almost 40 years ago. I know they're greatly improved, new electronics, uprated engines, improved rotors and transmissions, etc., but the basic design is over 45 years old.
They've got a long way to go before they outlast the B-52 .