When the Columbine school shootings happened you had someone -- I think from the SPLC -- going on and on and on about how the shooters had to be neo-Nazis since the killings happened on Hitler's birthday.
That didn't turn out to be quite right and the "expert" didn't have any real evidence for it, but his reputation, such as it was, probably didn't suffer from getting things wrong.
In this case, Coleman's biggest mistake was thinking that Islamicist terrorists are always going to be part of a well-trained, well-organized, well-financed groups.
Nowadays there are enough freelancers and amateur enthusiasts that you can expect a wide variety of expertise among al Qaeda supporters.
The upside of being a broadcast media expert or a “futurist” of any scope is that no one looks back to assess your past predictions or analysis.
It’s like predicting “could be” $5/gallon gas prices. It’s good for a headline but just idle smalltalk in the end.