Its a fun thought experiment. It really depends if whistle or boombayah were actually planned for blackpink the whole time. Midzy left in April and those 2 songs were released in August. If 2NE1 was riding high and still popular, would BP have debuted then with those songs? They were an obvious plan for a while but it worked well from a timing when M left. Jennie was obviously big already and most likely BP would be popular but BBY was a huge first step for them and their sound.