That was exactly the point. Early in the life of a new type of device (like a mobile phone, smart or dumb) there's a period of experimentation. Then everything converges towards an optimum.
Keep in mind that the phone's primary interface wasn't always a keypad, it used to be a dial or a lever. The speaker and microphone were distinct parts rather than a single "receiver". And they all slowly converged to a couple of very similar optimized designs.
Keep in mind that the phone's primary interface wasn't always a keypad, it used to be a dial or a lever. The speaker and microphone were distinct parts rather than a single "receiver". And they all slowly converged to a couple of very similar optimized designs.