Its actually more up to the fans. Or rather it used to be. How it theoretically works is that, you have people playing characters, and how good a reaction they get from the crowd (or more importantly how much they get people to pay for tickets and buy merchandise), the bigger the star. So the fan reaction to them would determine how much they'd be able to earn, if they'd get higher booking (i.e. main event matches, wins, etc).
Wrestlers used to have to largely create their own characters (although often there was some assistance, and wrestling is a collaboration, it requires people willing to be "jobbers" to put over other people to build them up), but now the WWE seems to largely foist it on them, and they script promos and everything now (used to be up to the wrestlers more, which is why we got those awesome coked out of their minds promos from the 80s from guys like Hogan, Macho Man, and Ultimate Warrior). How much a wrestler got over would depend on various things, but how it used to be is that if you could do a good job of making it seem like a legit competition or fight, it would get over, as it was easier to suspend disbelief. And for heels it was about pissing people off.
Its more complex than all that, and there's a lot of other stuff involved (personal relationships, politics, the real backstage stuff actually often has more drama than the over the top storylines do). Some guys (Goldberg and Ultimate Warrior for instance) were able to get people to suspend disbelief because they weren't good wrestlers, or rather good at making it look good but be fake, they legit hurt people and were just actually throwing people around (not a good thing).
I'm trying to think of a good resource that could maybe offer what you want. Jim Cornette is great, but he's very opinionated and is definitely more of an old school guy. He has like a couple of podcasts going, with lots of stories, but there's some where he just kinda talks about how the business operated. There's some good YouTube videos that go into things like the history of wrestling promotions. If you're really interested I can try to dig some up.
I'm not a huge wrestling fan, its fun but often gets a little too much for me and I don't love watching it straight, but there's a healthy secondary platform that is decently fun. Like I enjoy watching OSW Reviews, where they basically watch old pay per view events and then comment about them. And there's a bunch of others doing that that I watch from time to time.