Just look at gidle's tomboy and ive's love dive.
tomboy views/likes is 86/1.6M = about 50x after 1 month (about 20x expected)
love dive views/likes is 49/1M = about 50x after 1 week (about 15x expected)
for reference, big bang's still life views/likes is 38/2.7M = 14x after 1 week
50x in a short time was usually just seen in nugus with few likes. For these bigger groups those numbers are EXPENSIVE.
Ad views are probably about 50M for tomboy and 35M for love dive.
At 0.02$ per view that is 1 million and .7 million for YT ads alone... so far.
The companies must be confident in kpop's growth to throw that kind of money around.