GTD since 2017
Next step: How does one implement GTD in an organization?
That strongly depends on your role in that organization.
If you are on the top you can easily establish some GTD-like workflow and define processes in a GTD-way.
The further down you are in the food-chain the more subtle your approach has to be. Maybe you get an opportunity to create or improve any processes in your organization.
But even if you are at the very bottom-line, there is still a way you can spread GTD in your organization: Implement it yourself, be on top of everything and look like you have fun doing so Eventually your superior will ask how you get all your stuff done and that’s when your opportunity strikes.
Just one last advice: Do not push or force anybody to use GTD. Because if you do so, they will implement it reluctantly and always feel a resistance to it. But give people guidance, if they ask for it.