Side note: I've always wondered how much potential is lost in the current generations because of the constant distractions (of all kinds). The type of deep and creative thinking that comes from boredom and a lack of interruptions can drive great change and ideas from a personal and societal perspective.
The switching cost of focus changes is a real issue in thinking in deep ways. And the cost of doing it frequently is definitely a drain and cause of atrophy in overall focus ability. Trying to rein in your ability to focus for longer periods of time is HARD. It's mentally and even physically uncomfortable.