Original sentence: It is very difficult for a religion to grow to this size.Most of the world's religious people adhere to one of a few major religions (Christianity, Islam, Hinduism, Buddhism).Most of these religions (especially Christianity) became established when they were adopted by politically powerful individuals.The religion of the common people took much longer to change (sometimes centuries)
Edited sentence: It is very difficult for a religion to grow to this size, and depends more on the luck than the skill of the religion's founder.Most of the world's religious market share is taken up by a few religions (Christianity, Islam, Hinduism, Buddhism).Most of these religions (especially Christianity) established themselves by penetrating the social network of the society's elite.Once this network was penetrated, the religion quickly controlled the elite of the society.The religion of the common people took much longer to change (sometimes centuries), but once the elite had changed their religion the change of the whole society was inevitable