They do, but the point being made was that whilst AWACS had big radars, the planes were were even bigger, and the size advantage of the radar did not counteract the size disadvantage of the plane itself.
In days of 15m^2 fighter RCS and less capable LRAAMs, it didn't matter, but now things have changed.
EDIT: The other thing to notice from the radar equation is that range is a term to the fourth power and RCS is linear. So a plane with a quarter of the RCS, only has a 30% reduction in detectable range.