My thoughts about Tamiya primers and the Tamiya company are thus:
Having been involved in the aerosol packaging industry some years ago,Tamiya should consider packaging
their sprays like the Japanese auto companies handled the "made in America" lobby. That is,ship all the components involved in their paints and sprays and get a few contract packagers to do the filling,labeling etc. I'd bet an airbrush that most of the supply problems would go away.