They hope that interface copyright will give them, in effect, monopolies on major classes of software. But Apple and Lotus are the ones who have actually sued. Lotus has won lawsuits against two small companies, which were thus put out of business. Apple's lawsuit against HP and Microsoft is also being decided by an appeals court. Imagine if each car manufacturer had to design a different way to start, stop, and steer a car.
Large companies have an unfair advantage wherever lawsuits become commonplace.
Since they can afford to sue, they can intimidate smaller developers with threats even when they don't really have a case. Interface improvements will come slower, since incremental evolution through creative partial imitation will no longer occur. Open Computing magazine reported a Microsoft vice president as threatening to sue people who copy the interface of Windows. Users invest a great deal of time and money in learning to use computer interfaces. Far more, in fact, than software developers invest in developing and even implementing the interfaces.