you have to be interested enough to pull off the road and go for a look. Not so many do that.
Most visitors were people parked up waiting for a flight to arrive at one of the terminals. Now they wait (and are encouraged to) at the Maccas up the road. The Southern Cross is almost impossible to actually drive to these days, unless you already know where you are going. No signage, and only one, now effectively by-passed, road that has the entrance off it.