"People who trust only you" is to managers as "code nobody else understands" is to engineers: job security, and a springboard for making you look like a hero and so getting you recognition/promotions. And it's hard to develop relationships like that, if you can't just wander over to those people and have in-person (i.e. not on-the-record in the company's logs) conversations.

To exactly the degree that your company resembles a feudalist society, you'll see managers excited to have their own physically distinct office units/departments/working groups, where they can most-effectively hoard and develop private talent pools on the company's dime. And you'll see them heavily resist anything that makes that talent-pool of theirs less private, e.g. WFH, cross-departmental collaboration, "war rooms" during emergencies, etc.