Hard to say...
Cyborg's at the time "purple belt" did not look very purple to me when she fought Gina. The way positions were won/lost were completely unacceptable for a purple belt.
It was a miserable brawl in which the stronger woman won.
I actually think Ronda would destroy Cyborg, even with the weight advantage, and I'm no fan of Ronda's.
Is Gabbi Garcia that good on the ground? I don't know...maybe. She has a HUGE weight advantage on Ronda.
I once saw Megumi Yabushita (a pioneer of WMMA and decent grappler/horrendous striker) dominate a HUGE Eastern European woman just with white belt level BJJ technique.
So it's a given that in WMMA, grappling is far more important than striking because women generally don't strike with enough power to change the course of a fight the way men do.
The future will tell how it all plays out, but I see differences in womens vs mens tennis, and I think WMMA will end up being a lot more submission wrestling oriented in the future. At this point, Ronda is the only one competing with sufficient expertise.
It has been a total joke watching certain other WMMA UFC fighters and listening to the announcers pretending that I'm watching some elite athlete or something.