The last time luffy lost and came back was against crocodile but physically luffy was way more stronger than crocodile , but now kaido is in a whole different level , luffy doesnt have any chance , doesnt have any hidden gear , he just lost as expected ,there will be another side in this battle , the ones who thought that luffy will just win and everybody become happy are pathetic. in katakuri fight , luffy didnt have to win , he could run away when left the mirror world , so it didnt really affect the plot.