Well, yeah, they still rejected channels back then, but it was mostly for if they had five subscribers, or their content was very, very low quality. It was a much easier network to join though, is what I'm saying. I think that youtube is pressuring these networks to have stricter requirements, because some of them, mainly fullscreen, were accepting garbage, spammy channels to make a quick buck, mainly the "reply girls". Also, with these network channels getting less views than their partners, that's often because they don't hire directors to make videos for their channel. Fullscreen for example only has 2 videos, and that's because they don't upload. When you make a network though, you NEED to have a youtube channel to connect it to.
As for sharing your revenue with the network, I actually just explained this in another thread a moment ago. I'll copypasta if you don't mind:
"You see, when you become a normal partner or get monetization, youtube works out a split rate with you. I'm not going to throw out exact numbers, but it could be an 80/20 split for example. With a network, they may offer you a bigger chunk of the earnings, like 90/10 or something. Then the network shares their 10 with google. This works because now, google has less adsense pages to constantly track. Even though they personally take in less money, they're spending less on bandwidth, so their profit increases. Everybody stands to benefit in that way. Of course, you should make sure that your network deal is good before you sign off on it."
Sorry about the long reply. I just needed to clear that up :/