Right- Casey Jones, Alabama Get Away, and Touch of Gray didn't garner much airplay. What bridge did you crawl out from underneath of? Must not have had great radio reception under there. You do realize you're condescension is positively offensive, right?
Furthermore, now I hear Uncle John's Band, Eyes of the World, Friend of the Devil, and even Ripple getting played on modern format FM radio, on stations that never, for example, play String Cheese Incident. (They do play the new Widespread Panic single, and it's a very good song too, maybe even great).
I forgot Sugar Magnolia, another Dead song that garnered air play on release and continues to do so until today, and Scarlet Begonias is something you hear a lot of nowadays, including a number of excellent covers of it.