A company that has large market share because it charges low prices is not a monopolist, especially if other, technically competent companies are circling it waiting for a sign of weakness. But in the high-tech industry that's chicken feed. For a shot at Intel's market share, lots of companies could raise the money in an afternoon. This theory contends that, once a company gets a head start in a field, it cannot be overtaken because software suppliers and customers will all go with the winner. Thus a competitor has no way to break the circle.
Network effect is a neat theory, but like many theories, it is hard to prove in practice.
Rather, these industries were transformed into monopolies by government fiat, usually at the behest of private companies. The most commonly cited examples of so-called network effect, such as the VHS videotape system, or the alleged superiority of the Qwerty keyboard to the Dvorak, have been refuted by careful researchers. In addition, network theory ignores the ability of real companies to respond according to their strategic interests. Such large companies are well aware of the risks of being dependent on one supplier for a crucial component. Individually and collectively, they have the clout to offset any network effects if they think the issue crucial, simply by ensuring that no supplier gets a monopoly.