Exactly.
Go watch some full Mike Tyson fights from the late 80s (not just highlights). Prime Tyson would have knocked out anyone in boxing +10/-10 years of his era about 90-95% of the time. Post-Robin Givens Tyson was a joke. But before all the distractions and leeches sucked the soul out of him, he was a killing machine with gloves. Power, speed, movement and low-center of gravity. People forget just how good he was in his prime.
The problem was in the '90s he just tried to rely purely on his power and pretty much just stood in front of his opponents with no movement. He went away from his boxing skills and became a brawler. So real boxers started to expose him.
If Rousey is a smart and technically sound fighter, I'm sure she'll bounce back. But if she mostly got by with power and intimidation (ie. '90s era Tyson), then she's probably going to keep getting exposed by technical fighters. Once the formula is out, every trainer is going to give their fighter the blueprint.