Why is Garnet the leader of the CG? Why not Pearl?

Pearl was already the apparent #2 gem in the rebellion when Garnet joined, she was the Terrifying, Renegade Pearl!

When Rose was around, she was obviously the leader. When Garnet joined in "The Answer", she was a brand new permafusion and brand new to earth. There would likely be much training necessary to bring out her potential as a fighter. We don't really know how Garnet and Pearl ranked relative to one another when Amethyst or Greg showed up, but we can assume Pearl remained Rose's closest confidant, and perhaps even lover, up until Greg at least.

But Garnet has been the obvious leader since Rose's departure/Steven's birth. Who put Garnet in charge when Rose left? Why wouldn't Pearl, the oldest extant Crystal Gem and a notoriously skilled fighter and tactician, who knew more about Rose's desires and wishes for the team going forward, be the leader?

Is Garnet's rank because of her future vision and power as a fusion - as in the most powerful gem should be the leader? Or is it because Pearl, as a Pearl, is actually uncomfortable being the #1, and is actually more comfortable as the apparent #2, even if she's more powerful from that position than people think?