I am saying that the US and Russia are only willing to reduce their respective arsenals to 5000 warheads each. 5000 warheads each are more than enough to destroy the world multiple times. This is when the US has the world's most powerful conventional military and Russia has one of the world's second-tier most powerful conventional militaries. These two countries consciously choose to each maintain world-destroying levels of nuclear weaponry even when they have world-leading conventional militaries, as well as two of the largest national territories in the world to absorb any attack, do not forget to count overseas territories as well as their mainland territories. For other countries with less powerful conventional militaries and less national territory such as China, their nuclear deterrence against aggression by such powerful countries will logically need to be a world-destroying level of nuclear weaponry in order to sustain MAD.
Where the 5000 warhead number coming from ?
The New Start treaty restricting the number of DEPLOYED warheads to 1550.
The level of this number coming from the expected capabilities of ABM systems, capability of first strike and so on ( I presume )
It doesn't count the strategical warheads, and the pits resting in storage.
The nuclear deterrence is not a logical step in any thinking chain.
The current situation is the direct result of the Operation Chrome Dome and company, that created an environment where the soviets ( just recovering from an war unimaginable for anyone in the USA) was forced continuously to match the exponentially growing nuclear delivery and warhead numbers of USA.
Several USA president had the "what stupid thing we done" moment later on.
The nuclear deterrence can works well with 30-40 warhead stored separately with the missiles, and require days of preparation to launch.
That has exactly the same effect that the current system gives.
Currently the existence of the mankind depends on the mood of an operator somewhere deep in a bunker. If he drunk too much Tennessee whiskey previous day then there will be an Armageddon if any malfunction happens in his systems ( before anyone start same ranting : no one know how deep is the delegation of launch authority is in any organisation, appart from a handful of people)