Is the real reason for humanity’s ridiculous sized nuclear arsenal a fear of war against NHI?

I have heard of all the interest in nukes from NHI, I’ve also always been baffled why we continue to make more and more advanced nukes when the 3 superpowers already have enough to wipe out the planet. The 3 major nuke builders are also apparently the 3 nations with crash retrieval programs. I’ve not seen any discussion around this topic so I thought I’d start it. What is everyone’s thoughts?