Speaking from a teaching perspective its not that difficult a lick, but with Marks playing that's very often the case anyway. Its not what's played its how its played.
I agree, but, as you wrote, that's the case with pretty much all of his licks. Yet, almost everybody seem to miss some notes here and there.
I remember seeing Phil Emmanuel saying on one video that: "Knopfler plays this simple lick in Calling Elvis". But then he misses some notes in his execution.
Many people think it's an easier task than it actually is. That's the case, for instance, of the famous MfN riff. Everybody say it's easy, but almost everybody play it wrong.
I also thought this would be an easy one, but it took me a couple of hours to figure it out correctly. Ok, I'm no pro musician, and even though there are some similarities to other licks that he plays, I still find that this is one of the most difficult ones to spot right.
Anyway, the purpose was to play it in slow motion so it becomes easier to spot for those who want to learn it.