It's pretty clear that the monsters of the week all over Equestria are accepted as minor annoyances of daily life and not as a major threat to the nation. Ponyville alone receives a moderate threat like a bugbear often enough for Octavia to just roll her eyes and deal with it.
But the Elements of Harmony only protect Ponyville
90% of the time. So what's that say about other, larger cities?
The only reason Ponyville needs the Elements' personal protection is because it lacks the military or police force of a larger or headquarters city like Cloudsdale, Manehattan, or Canterlot. Even without Twilight, the unawakened Elements were shouldering the exact same problems of Ponyville, because they were all able-bodied.
But who's responsible for overseeing the military's staffing and protocol, the system of laws to protect against mundane threats like pony criminals, the civil requirements of food, water, engineering, fire safety, and the elaborate grand strategy that allowed the modern Elements of Harmony to exist in the first place and (until the Cutie Map) directed and commanded them in defending the nation?
The Princesses. They work in the background babysitting the nation while the young blood do all the hard fighting. And if they go missing, the nation goes into a panic if nothing else.