Having thousands of nuclear missiles seems like overkill. Is it just some way to waste money on grifting? I understand maintaining enough for "mutually assured destruction", but after that it is pointless. Not blowing money for no reason is an easy win.
The nuclear proliferation situation is because the math of proliferation isn't based on how many times you can nuke the planet, it's based on a math equation using this logic:
We need enough nukes so that we can nuke the silos of the other side plus have enough left over to also nuke their cities.
So say the enemy had 10,000 silos, each with a nuke. We need 10,000 nukes to destroy those, then also another x number of nukes to take them out.
This means if the enemy builds 1 extra silo, we can no longer fully nuke them effectively, so we need to build another silo too.
You might have a few objections, like:
"But what about mobile nukes like on submarines?"
That sounds like a problem we could solve with even more nukes.
"But what if they become allies with another country that has nukes?"
Sounds like a good reason for doubling our nukes, just in case.
Essentially, the governments were just using spreadsheets to calculate how many nukes we "need", and the answer is "As many as every other country combined, so we can nuke their nukes, plus also enough to nuke every other country, plus a little extra just incase."