As I have read this letter, and reviewed much of the discussion, it appears that Steinway may be attempting to become a very exclusive brand, much like the Rolls Royce brand is in the auto industry...the issue, however, is that to make this move is about 100 years too late in the industry. It would have proven much simpler if not so many pianos were already rebuilt with "non" Steinway parts. In addition, many parts and materials from Steinway are supplied by other vendors, not all manufactured by the great piano maker.
Time will tell the true ramifications of this letter.
Notes From the Piano Bench
Questions and Answers and updated factoids concerning pianos in the 21st Century.