Rousey was arguably the UFC’s first true mainstream star. At the height of her fame, she was appearing in The Fast and the Furious franchise as well as other movies. The former bantamweight champion was a fearsome competitor and ran through her division. But she became a moody presence in front of the media and this turned fans off.
They lost patience with her after she handled her defeats to Holly Holm and Amanda Nunes badly. It’s a shame because her legacy deserves more respect than they give her. Rousey was under a crazy amount of pressure so it’s not shocking that she didn’t react well. However, regular people aren’t very sympathetic to these things (via MMA Fighting).