The purpose of science in singing is no to understand how muscles work so that a great voice can be constructed. We cannot possibly do that. There are too many variables in the way muscles can work together.
What science should do is show us exactly how all the great singers were able to make the sounds they did. How did Del Monaco, Caruso, Ruffo, Ponselle, Tebaldi, Mardones, Merrill, Nilsson etc. sing the way they did? What made that singing possible? How were there so many artists able to sing that way?
Understanding how their voices functioned by understanding the science of singing tells us how the vocal apparatus and body should be work to make those sounds. The science should also tell us what we need to develop to make those sounds. Many people are potentially capable of singing that way, but when the proper understanding and guidance isn't available to them it is not possible to reach that level of singing.
Many people know all the muscles, cartilages and so on. However, like I said, there are many, many ways that all of these can coordinate together, but some are much more efficient than others. That efficiency is what will allow the voice to be free.
It is very easy for a singer to believe a free voice is a lightened voice; and that is what is taught today. If the voice is lightened it can feel easier, but only if trying to sing bigger and heavier is done with constriction. The constriction will make singing big very difficult. So the constriction is the problem. That is what must be eliminated so that singing big is possible without having to struggle. Singing lighter lacks power, harmonics, and is not as rich of a sound. It is not the sound required for opera at all.
The greatest singers did not sing with this idea of a light sound. They sang with a full, rich voice of power, range and dynamics. That is what we all should be striving for. That is what the greatest singers did and that is why we need science. To show us the path to getting there.
Edit to add:
Always remember that when scientists today hook up equipment to singers to see what is happening with the voice they can only go by what that singer is doing. They are not hooking equipment up to Tebaldi.