YGs style of "quality over quantity" won't survive in 4th gen. I mean they ruined 2ne1. Yes BP is a global success but that has more to do with BP than YG management.
BP is big enough that they can survive a 2-year hiatus just fine also when they debuted their songs stood out. But with 4th gen things have changed. The competition is cutthroat and you need multiple comebacks to make it through. There are so many groups doing so many styles the regular "girls crush" wont be enough.
Look at IVE within 9 months they had 3 CBs that cemented them as top GG, NJ released and promoted 4 songs for their debut, Lee Sserafim debuted in May and are already planning a CB, Stayc has had regular CBs as well. In order to survive in this climate, YG needs regular CBs for the group to survive, they can't have 2-year hiatuses.