You and Mjja obviously have no idea what a scientific theory is,grab those power lines out the front of your house and tell me if the theory of electro-magnetism is just a "theory".
it is exactly that - a theory.
Electromagnetism is a theory that explains observed electromagnetic effects. It doesn't explain where the theoretical laws came from, or how the particles came into being, or why a wave and a particle interact the way they do.
Until the 20th century, we had the "classical" theory of electromagnetism...it turned out to be wrong. But of course nothing, no electric motor, electric generator, power transformer, or wireless transmitter or receiver stopped working when it was discovered that the classical theory of electromagnetism was wrong. All those devices were (and still are) built according to a flawed understanding of electromagnetism.
Today the latest theory of electromagnetism is called "quantum mechanical" electromagnetism, which is a superset of "classical". QM electromag explains electromagnetic effects on a quantum scale, so we can build all sorts of new stuff based on an understanding of QM electromag, and all the old stuff based on the classical theory.
In any case, the QM theory is certain to be wrong, and when it is extended, everything that we've built based on it will not stop working.
Of course despite the fancy sounding name, no one is closer to knowing the why. Effects are observed and explained within the QM theory. Eventually someone will come along and find some electromagnetic effect that cannot be explained by the current theory and we'll move on. Don't confuse a theory with knowledge of the facts. The only things in science that are axiomatic are things that we've defined ourselves, such as 1+1=2.