The error of your assumption is in assuming that they think like you do. They do not. You think that a massive hit with everything that they have is the only strategy that could possibly "work." You may very well be right. But they might be thinking that hitting us with one thing at a time, slowly building up the level of terror, and disabling one piece of our economy after the other, is the best way to go. They might think that such a strategy would be easier for them to pull off (which might be true), and they might think that such a strategy might result in our demise (which it would not). That it might not "work" is not the point -- the point is: do THEY believe that it might work. If they do, then that is what they will do, whether or not it makes sense to you and I.
The error of your assumption is in assuming that I think like they do. I do not.
You are also in error when you assume the use of 1 nuke "is a massive hit with everything that they have". A single nuke is 5% of their capability according to the article. The impact on the world economy if one of these weapons was used against the oil fields of an OPEC nation would be immediate and, depending on how dirty the bomb, possibly irreversible for at least a generation. You also are in error in assuming they prefer a Chinese water torture approach to destroying western economies. I contend that if they had the weapons they would use them and they would, as Jihadist, welcome our reponse.