One, is economies of scale. The more you share across a greater range, the bigger the profit margins.
The second, is seeing the cool tech developed for high-end cars filter down to even the most basic models.
VAG's modular infotainment system is an example of the latter. According to Car and Driver, it's set to feature in a huge range of upcoming Volkswagens and Audis. The MIB, known by its German acronym, will be based around capacitive touchscreens.
Though different to Audi's current touch pad system, used in the A6, A7 and A8, it will feature the same ability allowing you to write letters with your finger, rather than tapping virtual buttons.
Audi will stick with the touchpad and button system, but adopt the MIB architecture. Audi's system has already been previewed in the 2013 Audi A3's interior, at CES.
In addition to the letter-drawing ability, the capacitive screen--similar to that found on Apple's iPhone, and in Cadillac's CUE system--will also allow Apple-style sweeping motions to cycle between screens, or tracks when listening to music.
Another feature will use sensors to detect when your hand is near the screen. This would allow hidden menus to disappear out of sight when you aren't using them, but reappear as you motion to use the screen.
Several screen sizes will be offered, depending on the vehicle. Entry level cars will use a smaller, 5-inch screen, but sizes up to 8-inches will also be available, even on vehicles like the 2013 Volkswagen Golf. 3D navigation maps, and free updates will also be available.
The MIB system is a perfect example of the benefits found in both platform sharing and technology sharing. High-end tech in low-end cars is cheaper for the manufacturer - and better for the consumer.