Yes, these are the same type of people who thought Christine O'Donnell could win a statewide race in Delaware and were SHOCKED when she lost in a landslide defeat (even though every political analyst both right and left said she'd be crushed). There are some folks that are entirely divorced from reality and live in an echo chamber fantasy world.
Obama CAN be defeated. It will be with a strong candidate and the current GOP field is weak.
If it does happen, I'm not betting on a landslide. Things are different today than in 1980