I didn't find why. When you make a wave with a rope or on a water the speed of the wave is formed by the speed of the interaction of the molecules in it. I bel

I didn't find why. When you make a wave with a rope or on a water the speed of the wave is formed by the speed of the interaction of the molecules in it. I believe similar thing happens with the light in subatomic level. There, may be the spped of light is limited on how fast an higs boson interacts with the neighbpring higs bosons.