I think the shows you mentioned are popular for a few reasons...one is that guys like yourself,me and probaly many other on this site watch them becuase they all deal with the stuff that we do&enjoy building something with our hands,i even watch monster house it dosent have anything to do with cars but i like watchin guys build anything!even a extreme house

Then you have a percentage of viewers that watch those shows not becuase they know anything about them but becuase the shows popular so they have to "fit in" by watching them.

Plus have you noticed that there isnt anything on regular prime time TV thats worth watching! so the discovery chan has the only things on that are worth watching right now.

I think the shows like american hot rod,amer chopper,monster garage,etc.... will help to get the younger generation involved with the rods/muscle cars so the classics will survive another generation.