Yes, production appears to require quite a bit of technical sophistication. (The FBI was unable to reverse-engineer the 2001 anthrax powder.)
In fact, it may be that we have overestimated the danger of rogue states and terrorism in general, for now anyway. Many of us assumed that 9/11 was the first in what would be a series of comparable attacks, but it hasn't turned out that way.
And these people are not sophisticated.
All they can think about are atomic bombs.
Well, I'm not so sure about that. Do we really know that terrorists are actively trying to arm themselves with atomic weapons? If so, why didn't A. Q. Khan make it happen when he was running his network? It seems to me that it's the Western governments and media that are focusing on atomic bombs, along with the governments of Iran and North Korea.
Terrorists seem to be concentrating on what they can do with traditional weapons such as chemical explosives.
At some point, WMD in the hands of individuals or small groups will become a problem, but maybe that development can be held off for a while still.
Perhaps, but I don't think so. I guarantee that if on 9/10/01 you had gone around asking people what they thought about the danger of a bunch of terrorists simultaneously hijacking several airplanes and successfully destroying both Twin Towers, almost everyone would have laughed at you and said that the idea was preposterous and it would never happen. That's the way these things tend to work, the danger is always overstated until it actually happens, and then all of a sudden one day out of the blue it happens, and the danger isn't overstated any more.
I think the more likely explanation is that before 9/11 our country as a whole just wasn't taking this stuff very seriously at all, and now we are, and because we are, we've made it far more difficult for our enemies to actually pull a mission of that magnitude off, though I have no doubt that they would still like to try again.
My big fear is that it looks like our government may be slipping back into complacency once again, and that it our biggest danger. If we go back to the 9/10 mindset, there's no doubt that it'll be just a matter of time before we have another major disaster happen.