Pace / 007helicopter
I think it's all a question of mindset, as has been stated.
Glider pilots train for landing out and it's de rigueur when cross-country flights cannot be completed.
PPLs on the other hand expect to return to base or fly on to destination.
Diversions are taught, but generally in a controlled manner to a suitable alternate airfield.
Maybe the emphasis should be changed and when 'diversions' are necessary, due to weather or lack of daylight, these are coupled with the mindset that a precautionary landing may be required if a suitable airfield cannot be reached. Diversion to a pre-planned precautionary landing (hopefully at some form of suitable 'airfield') rather than the precautionary landing being an emergency.
Not much difference in training requirements necessarily, but possibly a giant leap in respect of mindset regarding 'options'.
However, the overriding factor must be fear and uncertainty. Landing a light aircraft in an unknown field, as 007helicopter points out, with little training or experience (especially in poor weather and/or failing light) is no small undertaking. I'm not sure I'd be too happy faced with that prospect - which is no doubt why so many press on hoping that the outcome will be better than the field landing option.
The superior pilot is one who uses his superior knowledge to avoid situations which require the use of his superior skills!!!
In other words time spent on flight planning and threat and error management will significantly reduce the possibility of a hazardous situation arising in the flight.