rousey has the slickest ground game in womens mma, and is probably behind only to maia/aoki/jacare across the sport.
shes an olympic judoka. she medaled.
and then she let an LA armenian named edmond convince her she could stand, and she won a few fights because womens mma fighters are mostly garbage.
and then she got in the ring with actual legitimate standup fighters (holly and nunes) and got lost in the sauce.
we've seen this before. maia comes to mind, as ive mentioned. but her ground advantage is so massive in this sport, the hardest thing for her right now is extricating herself from the people who let her think she had a viable striking game.
once she does that and starts training with people who are going to teach her proper evasive boxing footwork and head movement, not to build off of for striking but to build off of for takedowns, she will get that belt back.