What is the point of High-End ($$) A / V wires, when it all comes in on Coaxial?

It dawns on me that HD cable service and HD satellite service come to my components by coaxial cable. Now, most everything I have ever seen about quality levels from different wire types shows coax at the bottom of every list. So, what is the difference between the wire that brings in the signal, and the wire that connects to my components? Is it because the signal processors that use the coax connection are anlaog, only? If coax can bring the HD digital signal to my house, why can't a TV use the HD signal on coax?