Instead of obtaining all 4 RPs, why did none of these 3 ever try to capture Rayleigh and try to torture the info out of him? Even if the reason is that Prime Rayleigh is on their level, so they didn’t want to mess with him for that reason, they have their crews to back them up and guarantee that they could beat him easily. Big Mom at the very least would probably have known through her intel network that Rayleigh is on Sabaody
+ depending on the timeline early retirement or long retirement time Rayleigh. It would be basically a full blown war between one's crew and Rayleigh.
I don't think Kaido or Big Mom were at enough power level when Rayleigh finished his journey to attempt to fight him.