The perenially readable Ross Douthat, in the New York Times, writes about the disappointing lack of cults nowadays.
The argument goes like this. So far as religion is concerned, "spiritual experiments led by the charismatic and the zealous are essential to religious creativity and fruitful change. From the Franciscans to the Jesuits, groups that looked cultlike to their critics have repeatedly revitalized the Catholic Church, and a similar story can be told about the role of charismatic visionaries in the American experience" (and we get to Mormons). (Nothing wrong with this. I can name one Catholic priest who has expressed the view that we need some new heresies.) Meanwhile, more broadly, "every transformative business enterprise, every radical political movement, every truly innovative project contains some cultish elements and impulses — and the decline of those impulses may be a sign that the innovative spirit itself is on the wane". So across society as a whole, we are left in the sad position in which "it’s not just that alternatives — reactionary, radical, religious — to managerial capitalism and social liberalism are no longer much embraced; it’s that our best and brightest no longer seem to have any sense of why anyone ever found alternatives worth exploring in the first place."
I think the short answer to this is a quick look at the news. The people who are known as ISIS, ISIL or IS would seem to fit the description of having an innovative project with some cultish elements and impulses, and I'd say that their project is a reactionary, radical and/or religious alternative to managerial capitalism which they are exploring. In short, I don't think we need to mourn the death of cultlike groups quite yet.
Douthat concludes: "Perhaps the sacrifice is worth it, and a little intellectual stagnation is a reasonable price to pay for fewer cults and Communists. Or maybe the quest for secrets — material or metaphysical, undiscovered or too-long forgotten — is worth a little extra risk." I don't know. I feel sorry for David Koresh, and I'm not worried about Mormons - but I'm not willing to run the extra risk of beheadings (perhaps in Oklahoma or London) to pay for them.