It's partly due to cultural reasons. In the 1980s, most cars still looked quite neutral. It's different today. Cars can look cute, but they're also allowed to look aggressive – the kind of car you'd want to make way for. In both cases the shape of the headlamps plays an important role.
They give cars a 'face', a piercing expression, a kind of brand signature. But, of course, new technologies are also opening up new dimensions in design. This is being driven by developments in LEDs and lasers.
LEDs have eliminated the paradigm of a light emanating from a single source. Traditionally, light always came from the glowing wire of the bulb. New technologies at their current stage of development are already making it possible to produce light across a surface area and thus to create patterns and designs. These are already widely used in daytime running lights, tail-lamps and brake lights. In tail-lamps, for example, the manufacturers are utilizing the properties of LEDs and OLEDs to emphasize the car's branding by means of a particular design. Headlamps, however, which need to direct their light toward specific targets, need to have optical systems made up of lenses positioned in front of the light sources. This involves a much greater degree of technical complexity. The more advanced these new technologies become, the more it will be possible to harness their properties for design.