> Phones sell because they made computers unintrusive

Respectfully, how does this make any sense? Didn't mobile phones end up becoming the most intrusive technology on Earth? (I'm not sure what you specifically mean by "intrusive", but I'm assuming that you mean "the extent to which the object interrupts your life/tasks/etc.").

Phones sell because they are:

1. Convenient

2. In most civilizations on Earth, it became a necessary item in order to live (authentication, payments, maps, etc.).

I'll skip the lesser points, such as the fact that they took over the camera for >99% of people for 99% of the time.