Here's the scenario in question. Your average person with a smartphone, who is not so technically inclined, downloads a game of some sort. The game upon first launch pops up a dialog which says "to provide you with the best experience, we need to clean up temporary files on your device, when prompted by the dialog (screenshot of system dialog), please press 'OK'." The user is then presented with the relatively scary system dialog which says "Allow this app to use system debugging features?", which they have seen 100 times and never understood, decides that this time they will press 'OK'. The game then proceeds to send all of their photos to a malicious actor for whatever purposes.

The average person simply isn't cognizant of the dire security and privacy consequences of many of the things that they do when interacting with a computer.

Note that I am NOT advocated for the removal of ADB. As an Android developer, I once used adb on a daily basis. I also love the idea of using adb to ftp my filesystem to my local machine for the sake of backups and whatever other useful purposes. In the case of the FireTV, I believe that if the device is put into developer mode, ADB can still be accessed over a USB cable. I think this great, and necessary for development and other use cases.

The point here is about making a system less likely to cause incomprehensible harm to the average person. Android and iOS were an opportunity to rethink the security model of computing (for computers that most people carry with them and use every few minutes), and I think that's great.