Well, going back to WW 2, we did have the "bazooka"- a lighweight rocket launcher tube- reusable- that fired a 2.36 inch diameter rocket. This was the US version of the German Panzerschreck. That was replaced by a larger launcher, firing a heavier rocket (3.5 inch). THAT was replaced in the late 1960s with the 90mm Recoiless Rifle- and supplemented by the single use M72. The 90mm would be a primary weapon, the M72 could be carried by everyone. It had less range, and lesser warhead. The 90 in turn was replaced by the Dragon, now replaced by the Javelin.
What we have here is... failure- to communicate.