Okay. So. Given that Rose is most likely not Pink Diamond, but Pink Diamond is no longer a part of the Homeworld insignia, I’m wondering if it’s possible PD joined the rebellion. Later than Rose and Pearl and Garnet, and possibly as a deciding factor.

I mean, imagine. Rose was probably a member of her court, possibly high ranking. Maybe they knew each other, maybe they were friends, or even something more. Rose rebels, and PD is conflicted. What does she care for this little planet? And she is at the top of the gem society, everything Rose says is wrong with how they treat Pearls and other gems benefits her 100%. So she doesn’t join Rose right away. But it eats at her, that her friend is fighting a war– likely a losing war, given the numbers. And maybe the new ideals she upholds make sense. 

In time, she can’t take it. She gathers gems, members of her court who come willingly. She thinks of Rose and asks for volunteers rather than demanding service. Some refuse, her Pearl included. PD departs to earth with a mismatch army.

That is threat enough to Homeworld, a Diamond turning against the others. But. Imagine if when she gets to earth, she defers to Rose. It’s her rebellion, after all. This is her cause and her war. Then Homeworld has to deal with a bigger threat to their social system than ever before. Pink Diamond must be crushed. She is, and after a long hard war so is most of her army. But Homeworld takes huge losses, and worse, the longer the fight goes on, the more whispers there are among gems, especially lower gems, about other ways things could be. So Rose wins her war. Homeworld retreats. Pink Diamond becomes a myth, an example for young gems of what can happen if they question the status quo.