OK, I'll bite... but treading carefully so as not to descend into a dark blue/light blue slagging match.
"How does that keep the level of SAR expertise and knowledge where it is now?"
I think you will find in all cases, 'SAR expertise and knowledge' is the same regardless of what colour Sea King you fly. Having known many RAF exchange officers through the years who have been thoroughly pleasant chaps this has proven to be true - albeit with a different con/patter! We just choose to do things a little differently and rotate people through different roles. What this means is that the number of SAR qualified personnel is much larger than the number of bods currently on 771/GSF.
"underlying ethic of the crews is 'SAR is a secondary role and anyone can do it'"
While SAR IS a secondary role for any helicopter, this statement in the way it is meant is utter rubbish. All personnel on the RN's SAR units consider themselves SAR aircrew. Long gone are the days of ASW with a bit of winching thrown in. There have however, been many rescues conducted by Lynx, Merlin & various mks of Seaking over the years (and even a few Chinooks!) that have been hugely impressive.
That is all
SKD