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.