:o)
Right?
The zero point field is gaining energy due to the latent effect of expansion. As the field gains energy more and more virtual particles are zapped in and out of existence. A photon packet of energy moving through the zero point field in the early Universe would not encounter many virtual particles, but that same packet moving through our Universe of now (in our region for the now perspective) encounters many more virtual particles popping in and out of existence due to the greater field energy. This translates to the speed of light slowing down as simultaneously the Universe is expanding and increasing in expansion. Consider what that slowing of the constant means to the electromagnetic reality of everything.