I've been working with Unity with the intention of making a large open world, and so this was one of the things I deliberately experimented with and tried to quantify. I found I had to be several orders of magnitude farther from the origin to notice stuff like that, and frankly I was a little disappointed that it was so hard to reproduce. Is there a sample project or description you could share that would help people observe that? I would not be surprised if certain circumstances other than purely distance make it worse. For example, when I traveled large distances solely on the world X axis, I saw my meshes quiver only when the camera was also aligned on/orthogonal to the X axis (don't remember which one exactly.)