Its really unavoidable. Computer software and hardware have become unbelievably complex. Look at what the avg computer runs today, this would have been unimaginable a decade ago and I'm sure the same will be true for the future.
The point is, the only way to sell new versions of software is to keep adding (often questionable) features and keep expanding the bullet list on the box. Its a sad fact that the majority of buyers (this excludes everyone here and on similar forums) will buy software based on the box art, website look'n'feel, and targeted advertising, with very little research. To be fair, they shouldn't have to. But everyone is greedy, we all want the shiny new features, and we want to have our cake and eat it too!
Writing simple software is very very hard. Its much easier to pile on feature on top of ill-conceived feature. More importantly, its the only way to keep the PHB's and suits happy and market it.