Exactly. But until that time...

Until a couple years ago, Pluto was closer to the Sun than Uranus, for twenty years. That's as close as it gets. It's mean distance from the Sun is 5.9 billion km, but it was closer than 4.5 billion km. In a hundred years, it'll get out to 7.3 billion km, and be two magnitudes dimmer. What else could be out there? It may take a while to find out.