True, though some companies are better at re-inventing themselves (GE, IBM and Intel, etc.), though not without stumbles along the way. I have seen successful R&D teams slowly torn apart because mgmt have put pressure on them to produce more products and less IP - only to kill the product pipeline in the long run (all while giving themselves far greater bonuses). And then they complain about turn over - duh!
I do not think it coincidental that those companies which do manage to reinvent themselves tend to be vertically integrated in some critically enabling manner (in your examples they all still retained their production facilities) that saw them through the rough times and managed to be leveraged into a competitive advantage when they re-emerged.
Apple is the one counter-example to this that I can think of. But Qualcomm, being fabless, basically only has its IP engine to rely on to differentiate itself in a perpetual sense and that is a difficult treadmill to stay on indefinitely.
When your business lives and dies by the popularity of your products on a 12 month maturation cycle, ugh, that is brutal. You are one bad management policy away from being RIMM or Nortel.