You can change other things to get the same result. You can build a consistent theory of aether by asserting that everything (including you) doppler shifts jus

You can change other things to get the same result. You can build a consistent theory of aether by asserting that everything (including you) doppler shifts just so and there is a 0 speed through the aether. You get a complicated theory that is not experimentally distinguishable and is incredibly difficult to use and noone would have any idea how to extend to QM or gravity because it's so cumbersome, but it's consistent and mechanics works. You could easily reframe the frame of reference in such a theory where the lab is moving at 0.999c absolute (which exists in this theory despite being immeasurable) as light moving very slowly in one direction and near instantly in the other.