Necessity of distraction in an executive's work lives is highly specific to their particular jobs. A good chief executive is essentially a hard-to-automate decision engine.
The principle of least resistance - in a business setting, without clear feedback on the impact of various behaviors to the bottom line, we will tend towards behaviors that are easiest at the moment.
Culture of connectivity persists because it's easier.
Responding to all the missives with alacrity makes you feel satisfyingly productive.
In the absence of metrics, most people fall back on what's easiest.
The principle of least resistance drives us toward shallow work in an economy that increasingly rewards depth.
Knowledge workers are increasingly tending toward visible busyness because they lack a better way to demonstrate value.
In the absence of clear indicators of what it means to be productive and valuable in their jobs, many knowledge workers turn back toward an industrial indicator of productivity: doing lots of stuff in a visible manner.
Deep work should be a priority in today's business climate.