That Bazooka nerf was a massive nerf so much so that the M20 basically disappeared from use after that and is rarely used now. The main reason why the M20 was good was because you could get 2 of them to inflict MP bleed that was not only cost effective fuel wise vs Stuart but was better than a single stuart while offering 2 bazooka vehicle crew squads which were useful at all stages of the game compared to a Stuart which has a 5 minute window of usefulness.
What is Stuart going to do vs Panzer IV? Nothing but Blind and hope it escapes however the 2 Bazooka squads could actually do something.
USF is ammo starved. Sure you can make the Vehicle Crew come out and give them Bazookas now but if the M20 dies then you just threw away AMMO on nothing which is why no one does that. The Ammo saved from the Bazooka was so huge that the M20 was used in almost every USF build and you saw the M20 every match. This meant you can get bars, drop an extra mine. No amount of buffs to the M20 made up for how massive of a nerf that was to USF which is why its a rare sight today despite it being one of the few decent things USF has.
Yes we know every USF has been nerfed to the ground...
On the other hand bazookas is not really relevant because using M20 to lay mine which was the original topic has become a lot cheaper (100mp /20mu/2 pop).