If Hinduism is more or less India's national belief system, this may be because it offers something for  mysticism and metaphysics for scholars, ceremony for ordinary people, austerity, sensuality, tranquillity, and frenzy.
Hinduism's popularity comes mainly from its mysticism.
mnli hypothesis: Hinduism's popularity comes mainly from its mysticism. premise: If Hinduism is more or less India's national belief system, this may be because it offers something for  mysticism and metaphysics for scholars, ceremony for ordinary people, austerity, sensuality, tranquillity, and frenzy.