It's probably a matter of age. For Freepers under 35, Rush may well have been their first exposure to a conservative voice with a significant audience. All we had was the print medium and, gradually, radio, until the internet became widely popular. National Review, American Spectator, and Accuracy in Media were my staples during the 70's and 80's.
You're right, never the less it's nice to know we hung in there till this all came together.