Imagine if the concept of a phone call did not exist. We still have these computers in our pockets, but without the history of the telephone system.
Then, one day, an app developer thought: Wouldn't it be cool if there was an app that would interrupt what the user was doing, play a sound, vibrate the device, and put up a full-screen dialog, that this all could be activated remotely by any other device by simply typing in a short numeric code, and that if the recipient pushed a button, the remote attacker could send audio data and activate the recipient's microphone? Most app stores would classify this as malware, yet here we are today with devices that all have built-in apps that do exactly this, and only because of how normalized the legacy idea of a "phone call" is.
Then, one day, an app developer thought: Wouldn't it be cool if there was an app that would interrupt what the user was doing, play a sound, vibrate the device, and put up a full-screen dialog, that this all could be activated remotely by any other device by simply typing in a short numeric code, and that if the recipient pushed a button, the remote attacker could send audio data and activate the recipient's microphone? Most app stores would classify this as malware, yet here we are today with devices that all have built-in apps that do exactly this, and only because of how normalized the legacy idea of a "phone call" is.