Unfortunately I don't think it's accurate. If you could tie it only to actors who had strong state support, I'd be a little less worried, because you can deter the state that is supporting many of those actors. With an actor like al Qaeda, deterrence is much more difficult because they don't have a return address you can attack that they really want to defend in the same way. That is not to say that deterrence is irrelevant. I think a variety of things like that are still relevant in al Qaeda's case, but are different than they are in the case of state-supported groups.
Al Qaeda's effort in particular was more significant than a lot of people realized. They made repeated attempts to get stolen nuclear material and recruit people with nuclear weapon expertise. They got to the point shortly before the 9/11 attacks of carrying out tests of conventional explosives for their nuclear weapon program in the desert in Afghanistan. The details are still classified, but I was surprised in an unpleasant way when I learned about them, because they're more sensible approaches than I would have expected for terrorists to take in a nuclear program.