No one is suggesting such a thing.
The ability to maintain effective and skillful communication in a world of constant distraction will be essential in the coming decades. "Protecting" a child from such a smartphone will produce an adult ill equipped to cope with the advances of the future.
No.
The ability to avoid constant distraction will be one of the most critical skills. The ability to focus, to think through a problem, to write a substantial essay, to plan, to evaluate your goals, values and priorities in life. These skills will be critical to flourishing in the coming decades (as they have always been).