What I don't get- Godzilla

How come the JSDF hasn't killed Godzilla in any of the movies. They killed him with an oxygen destroyer in the first film in 1954. Why don't they just use it again? Or better yet if he gets in a city, hit him headfirst with a 5 megaton nuclear bomb. Nothing can survive 5 million tons of explosive head first, even the king of monsters. Blast pressure is powerful enough to destroy him alone fuck the radiation and fallout. If nuclear bombs don't work. Why don't they just use a kinetic weapon like THOR? He couldn't survive a 1 foot wide 20 foot long tungsten rod dropped from orbit falling at 24,000mph and striking with the force of a small tactical nuclear bomb. Speed kills. Why hasn't the JSDF killed him yet? (Not regarding Japan's policy on nuclear weapons)

Posted by TachiMichi
as a Japanese,
allow me to say,
Godzilla is unstoppable!
No one can kill him.
He will forever last.

Hehehe. True that. There's a reason for why he's called GODzilla. In short, that kaiju atomic breath having lizard will never die. He's a walking nuclear weapon I say. Loved all the movies with the exception of the 1998 American adaption.