Atari historians have been able to find documents and tapes of chips and hardware developed at Atari. E.g. http://atariage.com/forums/topic/154479-new-gtia-chips/ .
Nothing like this is happening for Commodore and Amiga.
MOS designed tens (hundreds?) chips and this was its core business. It is hard to believe that a corporation owning a chip foundry lost all the tapes and blueprints of its chips (I mean not only the Amiga chipset) AND the companies who acquired the rights of what was Commodore did the same.
Why such artifacts don't resurface? How MOS archived such artifacts and where?