Excellent appraisal but at one place I felt inconvenient where you say Buddhism is gaining ground. The question is whether religion, like democracy, is legitimised by numbers although that is the most easily available and visible parameter for comparison or evaluation. [TNM55]
Religions which grew in pre-modern days have their own trajectories and time-frame. But a modern religion like Savitri Era ought to be different although many elements remain the same. The intellectual or Ontological underpinning is one major difference; the recent life-stories of the founders is another. The historical backdrops like the World Wars or Colonialism add a certain tension. Eminent contemporaries, moreover, provide diverse narratives for comparison.
Although, we have no means to display the results of Yoga practices as taught by The Mother & Sri Aurobindo, there is no ground to refute them either. Science has not been able to explain fully our existence within the Universe so far and hence relying upon Sri Aurobindian Ontology is the next best option. With all these advantages and swift communication mechanism, growth in numbers can come in a very short period with some message going viral in matter of a couple of hours. Sri Aurobindo perhaps alluded to such a situation by "hour of the unexpected." [TNM55]