It's very well written for sure. Though I may not agree with you final inference of religion being as scientific as science, but I agree with your flow of thoughts. The reason for former being a part role of religion was as a tool to explain the nature, yes. However when you say being scientific , I end up thinking of your words - 'field of enquiry'. Science is defined and systemized field of enquiry. You find a correlation and mechanistic insights. Now rishis must have done that, and they might be close to doing science as we know it today. But that juat makes them rational thinkers. It is not necessarily a comparison between science and religion.
PS: A very thought providing article.