The inner moons are more dense than the outer moons. The inner moons have more impact craters than the outer moons. The inner moons have a lower temperature than the outer moons. The inner moons spin faster than the outer moons. Titan have about the same mass, Titan has an atmosphere, but Mercury doesn't.
Mercury rotates slower.
When dinosaurs roamed the Earth, an Earth day was only 22 hours long. Jupiter's moon, Europa 24. Which of these sources of heating for the Earth has become more important with time. All of the above sources have either remained the same or decreased with time. Saturn's rings are further from the planet than its outer-most moon.