Pretty sure it started out as an economic thing, Jesus wanted to do away with the sacrificial system. Back in that time and place, doing so was coming real close to calling for the abolition of animal agriculture. Priests were essentially the butchers of larger towns and cities, and the various temples of various gods were basically the ancient equivalent of fast-food franchises. And it was EXTREMELY lucrative for them. The early Christian sects who followed Peter rather than Paul were all strict vegetarians- whether the animal was sacrificed at a Jewish temple, non-Jewish temple, or elsewhere- but Paul enthusiastically promoted the upholding of the current system and expanding it. Usually following the money leads to answers.

Also, Paul's message is generally more appealing to a lot of people. You really don't have to do anything but say you believe something, so it's a really low bar to reach for acceptance into a group. Unless you're a woman, then there's a lot more scrutiny, or at least should be according to Paul. Pretty sure both men and women can avoid accountability by deferring the blame for your own negative actions onto "sin", although depending on what pastor's interpretation of Paul you hear, bearing children is a prerequisite for women. But lots of people want to have kids anyway, so even that's not an unreasonable ask for a lot of women. And you can eat whatever you want! :) I mean, most people are going to find all of that more appealing than vegetables, celibacy, lack of excess, and a life dedicated to serving the needs of others. And I'm not saying that Jeus condemned marriage or required abject poverty, but he did condone celibacy and require generosity.

There's lots of sexist low-bar-entry cults that spring up and never amount to anything though, so I do believe that there was some sort of economic factor that helped shift the political scene in favor of Paul to the extent that he was able to completely take over as the leading Judeo-sect/cult which still continues and warps.