Then and Now

I got a birthday card today from our insurance agent. On it was a list of statistics then (1979) and now.

New domestic car  $6,474         $20,690
Average Income    $22,178       $49,800
1st class stamp       $0.15           $0.44
Bread                        $0.50           $3.19
Gas(1 gal)                 $0.86           $2.69

And I had an epiphany: No wonder everyone is in debt. The cost of living has tripled but the average income has only doubled.
Why is that?