@TheMurderousCricket In short and simple answer Yes.
AFAIK, The reason this happens(Invisible roads, invisible Other components) is because of occlusion culling. It's a technique used by many game engines(Unreal Engine, Unity3D). It simply disable/hide the game objects(for Non Static) & layers(for Static Objects) which are out of the camera's draw scale.
So in simple words, GPU & CPU only needs to render the game objects which player(Player's main camera) can see. Gameobjects are not needed to be rendered processed which are out of this range.
Apples and oranges, really. Naturally, objects far outside the scope of the player, will not be rendered (nor objects within a ymap governed by the entitiesExtents* value, when you are outside of these bounds).
What TheMurderousCricket is talking about, though, is the fact that Menyoo's camera is assuming a fixed 'start-off point', as it were, where the farther you move away from that position, LODS start to kick in, so roads/bushes, etc, will all become fuzzy when you panned too far off. 'Occlusion culling' is simply not related to this phenomenon.
As for despawing, apart from cars and peds (outside range), normally actually nothing despawns. Ere the opposite: objects you manually despawned (or with a script. of course) will return after a while, when you were away in the meantime. The way a script tends to handle this, is to re-despawn these objects (usually based on proximity to them).