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It may be an oversimplication but as a summary of IBM's history of reinvention, I don't think it is all that wrong.
Oversimplification? It is like summarising the history of human transport by saying that man went from horses to aeroplanes in the 1920s. It belies and conflates everything that happened before and since.
Whilst IBM may have had 75% of the typewriter market around that period, typewriters were a minuscule part of their business at that point. Both in terms of volume, sales and staff.
As for NT and *nix - ... I might be remembering someone reporting the DEC hirings and just assuming it was DEC UNIX rather than VMS that ended up in NT.
That's a common but very erroneous retrospective rewriting of history.
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