Why MEG is not sensitive to inhomogeneous conductivity profile of different brain compartments (scalp,skull and brain) but EEG is sensitive to that?
MEG measures magnetic fields and EEG measures electrical potentials.
One property of magnetic fields is that organic matter (scalp, skull, and brain) does not block them in any significant way.
Electrical potentials measured on the scalp, on the other hand, are definitely affected by the matter between the source of the signal and the location they are measured. This is because the scalp, skull, and brain provide significant resistance to the flow of electrons.