[a few thoughts]
we can mean a person who is popular with a following, a so-called 'cult of personality', yet typically we mean a person who run a group of extreme devotion, or a charismatic guru who gathers followers to his or her self.
At a push you can call a scammer a cult leader, with Peter Popoff he is a guru of sorts, a scammer, sure, yes, and indeed uses his ministry to gather funds, it's a racket, a front, he has a pet cult on a lead to get money, yet there are worse things than greed alone.
David Berg, also known as Moses David, ran a group known as the Children of God, since changed it's name a few times, and he wasn't in it for money, he was in it for lots of sex with underage-girls, he was a narcissist in the extreme, and created a faith to allow him to live out every fantasy and perversion.
There are many reasons why cult leaders become what they are, in the sense of position and the abuse they offer, the everyday western guru, new age or otherwise, doesn't often form an organisation, they are selling a product. And usually not on the scale of Popoff, small business models based on lectures, books, and worshops, no big clean up scam, lots of small plays that are not easily regulated.
Narcissists are commonly the type of people to create cults, socially insecure people are often the best followers, the narcissist hungers for position, the rest are dominated, indoctrinated, or expelled.
The average Newage speaker isn't a cult leader, they are a sales person with a willing and credulous audience, same for many christian speakers, they may make vast sums of cash, but it's more about the money than anything. And these sorts of people are rarely true narcissists.
The Narcissistic Cult Leader is one who isn't so much after money, sex, or any such thing as such, it's all about what Sam Vaknin, an expert on Narcissism, calls 'narcissstic supply', the sense of gratification that comes of having their own way. And remember the worst thing you can do is remove that supply to the narcissists ego, it is their life's blood, and extreme cases will do anything to ensure they get it and keep such a supply within their power.