But, dear Fr Steve, their goal as stated is to prevent obscure words from becoming extinct. No word that is in the OED will become truly extinct so long as there remains in existence one copy of that massive set of books, just as no ovscure word in Chambers will become a part of anyone's daily vocabulary.

In terms of preserving the words, they need only be writ large once, don't you think?

Certainly, if the Chambers people decide to do so, they can produce on volume with nothing but endangered words in it, but of what use is it? The OED is the gold standard -- Chambers is aluminum.

TEd