This is the case in most places that we (in the US) would not really care if they had them to begin with. In problem places, this is not really the case. North Korea for example cannot really afford it, yet they have now tested two weapons. Even Libya had a program, they can barely afford anything either.
This is laughable. Sorry, but the Russians have tested new delivery systems pretty recently, as well as done serious upgrades to its tactical nuclear force.
I doubt Ukraine will ever be in NATO, but that is another issue. Additionally, the Russians have now moved beyond the SS-18/19's. While certainly not in the same scope as in the Cold War, they have upgraded the delivery system. We in the United States have done nothing except downgrade really back to the Minuteman III, and we have more or less made those single warhead missiles.
Nuclear force that works.
This is a pretty simplistic rendition, but I will go along with it.
I want to assure our allies that our extended nuclear deterrent is credible. A reliable and credible deterrent prevents proliferation. In a place like Japan that matters, in a place like Taiwan it matters even more. Do you think that China would have not invaded Taiwan by now if the US had not given Taiwan a security assurance? If China knows our arsenal has atrophied and we won't use it, then what is to stop an invasion? The only thing that would stop an invasion would be a Taiwan nuke, which if they started that program would cause an invasion.
We need flexibility in our response yes. We need to be able to target everything you just mentioned, not throw our hands up and say "oh well, its to difficult."
