The only bad news is that 190 stunk so bad that they may well have lost some of that momentum.
I wouldn't bet on that. The media buzz post-fight was even bigger than post 184 and that translated into a 40%-50% bump in PPV buys.
My money is on Rousey at least matching and possibly exceeding UFC 190 on her next card. She hasn't gone anywhere near the sort of media saturation that you would expect prior to a fighter popularity decline.
My personal feeling is that Rousey is entering "event television" territory ala Tyson or Jordan. People are tuning in just so that they can say that they saw it.