Re Baldrick, you should not dismiss his work as the mindless repition of a meaningless piece of onomatopoeia.
That is like calling those men who went out to save Europe stupid, stupid.

He clearly uses the word boom as an antonym for bust.

Boom, the British army morale was booming!
Boom, the new technologies of tanks and air power were booming!
Boom, the new tactics of creeping barrage and combined operations were booming!
Boom, British and allied troops pushed the invaders out and ended the cruel occupation!
Boom, boom, boom, boom,.........................