Perhaps that Lookout needs to be improved....so the question might be why is that?
Pilot technique, complexity of the cockpits, cockpit workload, flaws in training?
probably all of those areas plus many more, not least of which is more congested airspace.
GA, whether flying for pleasure or learning/instruction, is forced into fewer areas with other (perhaps incompatible) airspace users (gliders and microlights vs Cessnas and Robbies for example) for a variety of reasons, one of which will be that the relatively low costs of GA have encouraged many more people into the air.
As I have alluded to before, the most dangerous time is a good weather day either just before or just after Winter when the whole world launches airborne.
Maybe we now have to treat other aviators as I was advised many years ago to treat other drivers on the road - assume they are all idiots out to kill you and plan accordingly!