The point being why does a greater energy source produce more light, but always produces light of the same speed.

Replies to date refer you to Quantum Theory (QT). Open any starter text on QT and in the introduction you will find a comment to the effect that QT has no complete interpretation. QT physicist operate in the belief that if you can compute it, you understand it.
This means that there is experimental proof and a mathematical theory that states the known facts about 'light'; but there is no explanation of how or why it operates in the known manner.
This question of interpretation (reasons stated in words) is the one I am working on. You can see the start on the webpage I referred you to on the waves discussion. I hope to open a discussion on this when I have made a little more progress.