[vortigern]

The main technical difference between AM and FM radio lies in how they encode the audio signal. AM varies the amplitude of the carrier wave, while FM varies the frequency. AM radios are relatively simpler in design as they primarily involve the modulation and demodulation of the amplitude of the carrier wave. AM radios are generally simpler in design compared to FM radios, which can potentially result in lower manufacturing costs for AM radios. From a cost perspective, there is no inherent reason to exclude AM functionality in car radios.

[Myrddin]

FM requires a stronger signal to achieve "full quieting". In the FM world, the strongest station always "wins" by capturing the receiver. AM signals can co-exist at very weak levels. That is why aircraft communications use AM. You can hear strong and weak signals at the same time. The advent of software defined radio allows application of digital filters and demodulators that are superior to what an all RF hardware solution can achieve.