The same architecture had to be scaled to fit anything from the largest full-screen displays to the smallest quarter-panel devices to allow transfer of learning and a common user experience. This had to be done while maintaining the a usable touch-target size and readable font size.
Collected usage data taught us which 20 percent of the features are used 80 percent of the time. We exposed exposed those 20 percent on the first tab. This was easiest when using the largest displays. (Note: I contributed to this design but it was a team effort developed over decades.)
Many of the office multi-function machines used a panel half that size. We found through testing that maintaining the width of buttons was more important than the height.
Some feautres (such as Reduce/Enlarge) were collapsed into a secondary screen but still gave feedback of current settings.
A higher resolution and lower cost led to the 7-inch full panel. The button target sizes needed to appear the same to end users so that layout was adjusted.
More of the features are now collapsed into secodary buttons.
Lowest cost desktop machines also needed to support multiple features. All the features are now collapsed to secondary screens but they maintain the same UI architecture.