Media deployment tends to follow a given sequence. Text is the easiest medium to place in courseware and is always present. Still images, such as artwork or graphs, are second. Next sound typically comes since it requires little additional hardware. The current challenge is providing video into courseware.
Good video is difficult and expensive to capture, store, and reproduce.
It is relatively easy to create courseware that presents lessons in a linear fashion using only text. This is the basis for books. Creating courseware that uses video costs a great deal of time, hardware, and developmental software requirements. Second, providing such courseware for student use requires more powerful hardware. Third, creating software that provides extensive learner-control requires extra time and effort.