The Scorching Sun Department isn't incapable of discovering Ghosts, nor are they unable to make devices that can detect Ghosts' presence.
It's just that the special materials needed are in very short supply.
The best resources are all used where they're needed most.
At the very least, a small town that's always quiet, losing population, and barely has any harmless Little Ghosts, would never be prioritized in resource allocation.
If an Evil Ghost hides its presence, always takes side roads, and doesn't cause any trouble, whether the Scorching Sun Department detects it or not, the result's the same—nothing happens.
The Scorching Sun Department set its core policy long ago: To focus on deterrence against Ghosts, because it's simply impossible to eliminate all Ghosts, let alone prevent new ones from emerging.
Excessively extreme measures were ruled out from the start.
