Firstly, I think what you are describing is the current situation in America where the massive production of weaponry is not practical.
ok....so if US is practicing large scale weapons and ammunition production currently AND NOT succeeding much, isnt that the best sign a big war footing ramp up of production is likely to fail also?
But, come to a 'war footing' like in World War II, America still has the capabilities to focus a large part of its economy for large wars.
If US can't ramp up weapons production sufficiently TODAY for its allies like Ukraine and Israel, i think that strongly suggests it wont be able to do a successful "war footing" military production well...its a big hypothetical- US stole the Australian submarine contract from France and can't deliver it- labor and skill shortages are endemic of US economy today and its defense production cant fix that issue overnight- these are long term issues that are hobbling US production today- it'll probably take US 10+ years to try to get into a better production tempo.
The country is essentially self-sufficient
No its not- COVID showed us all the things US imports from the world- look at Russia- even though US sanctioned RUssia, it was after the sanctions we saw all the commodities and products that US imports from Russia. Why has US had some types of shortages remain since COVID then if its self sufficient? I now heard ADHD medicines are scarce- something is always ain shortage these days.
and perhaps the most strategically blessed country in the world considering human and natural resources along with the protection offered by two giant oceans and just two land borders and that too with friendly nations. But hopefully we will never have to test what I am saying here.
that wont save US or its people from over-extension and collapse of its
empire economy due to foolish strategic mistakes like fighting the world with a weak economy and weak currency and low military capacity (relative to military needs). foolish, unwise and untimely moves and decisions can neutralize any human and natural resources a country has. Truth is that US today is struggling, even if it doesnt seem that way from the outside- signs of objective success are hard to find in US today. Even the CEO of Rheimentall recently said that EU ammo warehouses are empty while China and Russia have lots of weapons- the west has gotten exhausted already, so if they enter a new global or regional war today, they will not do well- they dont have all the time in the world to prepare for it, because by then, their adversaries would be in dominant unbeatable postions.