Perhaps the arrival of GPS and glass cockpit, things have changed in the minds of the pilots?
It seems to me we are in a transition, where ultimately we will be given GPS navigation which will include NOTAM compliance and warnings, almost like automated flying with the pilot there to check what the machine does?
Thats not so far from the big ships flying, where hand flying is sometimes actively discouraged!
It could be "airways style" routings (though not airways restricted, VFR) but could also be "approved free flying boxes" with warnings (3D) at 1nm and 0,5 nm from the edges