They don't have a spare 10 hours to learn the basics of some new software, or another 50 hours to get really good at it. For Linux experts, learning a new application is relatively simple. For most computer users, it is not. Users are incorrectly resistant to change, the argument goes, when they should be accepting something that is new and better. This is backward thinking.
People create computers to do the things that people want to do.
It is not the job of the masses to adapt to your computer system. The history of business is carpeted with extinct companies that did not understand this. A good example to follow is Palm Computing, which understood what people really wanted to do with handheld devices, and captured the market as a result. Microsoft Word and America Online are near the top of this list. To speed development, initially it can include just the most commonly used subset of features.