In my experience a lot of people don't realize you can get network TV in HD with an antenna. The cost of cable is just way too high to stomach given other available options, the best option being watching less TV.
Do people in your area skew towards a younger demographic?
Here, widespread cable tv became dominant in the early 80s. A lot of us had to use antennas to watch local tv on the main or secondary television sets in our homes.
I haven't polled anyone but I can't imagine that most people aren't aware that network tv can still be watched over the air.
