We've got to get back to who were protecting here.
I'm sure a lot of VFR bugsmashers would like not having to talk to anyone.
Captain Figjam and his pax though need to know that the VFR may be in the way, hence if a place is busy enough for it's own CTAF then anybody in the vicinity (did I hear someone say 15nm/5000ft MBZ??) needs to be on that freq. If they are somewhere else, then Capt Figjam doesn't need or want to know (nor do ATC).
If the VFR is going into Capt Figjam's territory (did someone mention above 5000ft outside 15nm?) then they need to talk/announce on... the Area freq.
So I can see a lot of sense in having, in effect, a huge broadcast area at lowish level on 126.7 (unless of course a discrete CTAF is warranted), as is currently effectively the case. All the low-level smashers on it and only pertinent broadcasts on the Area freq above it.
As for Creampuff's scenario, there will always be unique situations which might not fit the mould. In that case, it's up to the farmer to know the local area and make intelligent calls.