Corporation Reinvention

The last few years, many industries have seen companies with traditional/legacy business models really take a market share hit by newer business models or approaches. Recently it has been brick and mortar businesses being overcome by more nimble or cheaper methods of delivery (online streaming content, e-commerce, etc.). For me, a few come to mind: Blockbuster filing for bankruptcy (Netflix/Redbox), Best Buy losing considerable market share (Amazon), and RIM/Blackberry sales and revenue dropping (Android/Apple). I've also seen most of these companies take extreme measure to try and turn the business around via layoffs, acquisitions, plunging into the emerging markets/products that are dogging them, etc. (Yahoo, AOL, HP, RIM). My question is, has there ever been a company who has dominated the market with their flagship product or business model, later to totally reinvent themselves and at least stay competitive, if not remain on top of their respective market? At first I thought Apple came to mind with their consumer devices, but their first foray was into the desktop market, and I believe that at no time did they ever hold >10% market share to Microsoft.