Strategic execution is a matter of leadership
And leadership is a matter of employee engagement
It cannot be emphasised enough that strategic execution ultimately gets done by the people at the bottom of your organisation chart. It is also a well researched fact that these people perform better when they know what you want to achieve, not just what you want them to do.
This is the reason for being purpose driven as a company: so you can synchronise everyone in the company around the same purpose.
Don't believe the hype: your purpose does not need to be about saving the world (although it does need to be relevant to others).
Please note that employee engagement is a kind of "internal reputation management". Employees react to what you do, not to what you say. They base their level of engagement on what they experience from leaders.