No. Non-zero rest mass photons will break a lot of theories. Plus, the "speed of light" is not merely an experimental result coming out of an interferometer.

No. Non-zero rest mass photons will break a lot of theories. Plus, the "speed of light" is not merely an experimental result coming out of an interferometer. It's also a theoretical result, e.g. from Maxwell's equations - that's the one referred to by special relativity.