What about all those people I have to deal with who don’t do this stuff?

The more out of control your environment (including people), the more critical that you implement your own GTD process. You need to know what’s yours and what’s not, and manage your own “10 acres” with rigor. And as you hold new standards, it impacts everyone to some degree. Though there’s no guarantee, the more you manage your own stuff pristinely, the more people tend to engage with you at that level.