The theory of light has been expounded differently by scientists in different periods of time. What is an important reason for these different theories?

Technological advances clearly.

Theories change due to other peoples view on the matter and how they experiment with it, but Technology advancements are the greatest factor of all. I mean seriously, we wouldn't know of cells before the microscope and when they first invented it, it advanced further and now we can see things on a whole deeper lever.