Not just I feel tbh, but actually Min Hee Jin semi confirmed it when she was being interviewed about New Jeans and talked about how she already had these songs for a while in waiting. And that's not an uncommon practice, same thing we know from JYP, during one of Itzy shows he said his favorite Itzy song is the one they're yet to release in the future, which turned out to be Cheshire.
So what I am trying to say is that Min Hee Jin knew she had hits with these songs long before they became ones. But she certainly hasn't planned their entire career, right? At some point they'll catch up with material and will have to find new songs in rather short amounts of time and they'll start missing.
I think that's ultimately what happens to majority of groups, not just NJ. The same probably happened to Twice, they drank BEP and JYP dry and started shopping internationally and that's a difficult process because you literally have an ocean full of songs and you have to find the right one and do it quikly. And for the same reason YG was likely having these huge breaks between BP comebacks, otherwise Batter Up would've been a BP song long time ago. And Min Hee Jin can go that YG route as well, we'll have to wait and see.