""Don't forget, though, it's the academics who have revealed oodles about our past and who seek in their various ways to preserve it for our future".

Hmmm, rather topical. Sometimes then and now the academic mindset is apt to err too far towards learning at the expense of preservation. And then, in the wise words of a sage, there's "no learning to be taught, save that history's lesson Is never to be learned".
The problem arises, plain and simple, when the decision is the hands of too few. And if they happen also to be intellectually arrogant, well...

Wildwooder wrote: "I would have thought that wood in a wet environment with wind and tides would be bound to deteriorate eventually, so this seems a longer term option."

How long will a museum preserve the awkward pickled wood once interest dies down? Wood in a wet environment lasts indefinately in the absence of oxygen - that is the real long term option. That is why Seahenge has been preserved for so long. Ditto wooden trackways in Somerset and elswhere. Ditto Roman stakes on the Thames foreshore. Now, Seahenge timbers are chemically preserved and all you have are lumps of pickled wood to display. The academics have measured and analysed and then left us with an exhibit of ancient timbers. Location is all and without that there is nothing. Seahenge was destroyed by the archaeological establishment . It is exactly as if Stonehenge (or any other monument) was dismantled and some of the stones displayed out of context in a museum perhaps with a painted backdrop. Seahenge if left alone would have been in situ for generations. The sea may well have buried it again, but it would still be there where it was intended to be.