Christopher

Seems to me that the lessons we've learned were well encapsulated by your posting about "Re$toration in NYC".

WARNING:  Sweeping generalisations follow!!  

We've become pedantic about returning to the 'original', whether it exists or not.

We've become precious about keeping the original fabric intact, even if it doesn't work now, and maybe never did.

We don't know much more about prolonging the life of materials, although we do have some great patching compounds and some halfway decent waterproofing coatings which if we are lucky will last 20-30 years.

We have separated out work on the old and the new, with the result that the new is built without learning from the lessons of the old, thus ensuring plenty of work for those who will look after the old of the future.

WARNING:  This is all from somebody who wasn't even born in 1960, let alone know what was happening in preservation technology at that time!!!

Cheers

david

PS  Found it very interesting in recent months to find out that some of the pioneers of architectural heritage preservation (conservation, restoration) in Australia in the 1960s & 1970s were the same generation as the modernist architects here in Sydney and Melbourne.  Indeed, it would appear that there was a fairly close dialogue between the two groups (and that they overlapped).  Could we say the same now?