4 door values? Am I missing something?

I'm in the Northeast: I always look for 4 doors, they work for me. I've paid between $400 and $1600 for them. None of them have been nearly as nice as 64Dart170's past cars. I have noticed many people love that $5000 asking price, they don't sell. One guy on CL has had a 76 Valiant listed and re-listed for maybe a year and a half. He started at 5 now is down to $3500-still not going anywhere. Maybe a "museum" quality survivor with 10k on the clock would go high but I'm not interested in that.