Quasars formed and died during a limited period of evolution of the universe. High redshift objects emit limited visible light. Low redshift objects are undistinguished and difficult to find. Most X-rays come from nearby or very far away, but generally not from intermediate distances. Only nearby sources can give off detectable X-rays.
Most galaxies are too far away to see their X-rays sources.
No beaming is required. The calculated charged particle density is a function of inferred distance. Theoretical problem getting photons out from interior when density gets too high. No special problems arise. Some of those appear to be connected to the galaxies.