I guess it also depends on what you mean by success.

I think the period people look at as "successful" was the period up to Millennium and maybe a little after that, maybe through 1974.  During that period, Maharaji's arrival in the West happened to coincide with the hippie movement, and anti-war movement, and the "dropping out" of a lot of young people looking to just get, and stay, high.   

Maharaji sold knowledge during this period as the ultimate high, as God realization on the cheap and easy, and as a no-cost, no-committment, "try-it-you'll-like-it" "experience."  Who wouldn't want that?

There also was almost no "preparation" for knowledge and thousands of people were revealed the techniques, sometimes in huge knowledge sessions of hundreds of people.

So, there was a kind of "splash" in the sense that Rawat was visible, the premies were out there advertising the coming of the messiah, and the press took notice.  DLM went from zero members to thousands, but the vast majority left very quickly, and maybe there were 5,000 - 10,000 (at most) active premies in North America, with probably a similar number in Europe.  That number dropped throughout the 70s, and the cult did not grow after 1974, and in fact shrunk. 

The only reason Maharajit retained as many followers as he did in the later 70s was that he played the God card, and the fear card,  and moved from "get high" to "path of devotion" and "surrender."  So, the die-hards didn't leave, they got more fanatically devoted.

Once Maharaji let up some of the pressure on that, many of those people left as well.

And almost nobody received knowledge during that period, just like now.