Those were two mighty and proud companies, the first being the company that toppled IBM ( IBM) with its speedy yet less expensive midrange computers. The second? The Soul of a New Machine, just the most reliable boxes, so good that Michael Bloomberg selected them as the platform for the first Bloomberg terminals. Talk about an endorsement. Both companies developed proprietary technology that put them head and shoulders above the competition, and their stocks were fabulous gainers, the belles of tech, the ones you reached for first on any good tech news. And then they were gone. Just like that. Defeated by more powerful yet cheaper desktops with commodity, not proprietary, technology. The model evolved and made things obsolete. Better mousetrap. The three companies that ran hardest with it? IBM, Hewlett-Packard and upstart Dell. Eventually, IBM realized that it had no real value added. It was all a commodity anyway. It sold its PC business to Lenovo for $1.75 billion. People were thrilled that they did, and IBM's been getting a higher multiple ever since that sale eight years ago. IBM went into outsourcing and software and in the last few years has been a total home run. But Dell and Hewlett-Packard? They stayed with personal computers. HPQ had a superior printing business, and it also bought a consultant, but it made its bread and butter in the corporate PC market and then spread out through the enterprise. Remember, HPQ specifically went the other way from IBM and doubled down on personal computers a decade ago when it merged with Compaq. Dell was the cheapest and the best-run. It took the commodity parts, assembled them cheaper than everyone else and became the dominant consumer brand and ultimately the chief rival to HPQ in the enterprise. Unlike Digital Equipment and Data General, both branched out toward higher-value-added products (although you could argue that DGN did develop the first truly sophisticated inexpensive storage unit using bundled hard drives). Hewlett-Packard bought EDS, the consulting company, four years ago to compete with IBM and Accenture ( ACN). Dell made acquisition after acquisition to provide more value on big contract wins.