At the company that I work we have a successful software product that did well but is now obsolete and unmaintainable. I am trying to explain that you need to innovate and replace this product with new offering in order to survive. I am looking for some good examples of companies that made the mistake that we are close to making - relying on one successful product way over it's normal lifetime, so I could use it as illustration when making an argument.
These products need not be software, emblematic cases that illustrate well this situation but where product was not software are also appreciated.
VisiCalc for the Apple II was the first spreadsheet program (i.e. 100% market share) and is considered by many the killer app that made owning a computer important for business rather than as a hobby. In that sense, it paved the way for the PC, yet failed to make the transition to that platform well, and was supplated by Lotus 1-2-3 and later Excel.
WordPerfect was for a time the dominant word processing app. It fell prey to a delayed and low-quality move from DOS to Windows.