Specific to targeting teenagers, porn users are mostly under 30, so your statement about 14-18 being around the same as 18-80 is irrelevant. About not being able to pay at 14-17, sure, let's go with that, but they start paying after that. We are talking a few years here. Companies do have incentives to create customers just a few years down the line.
Let me ask a few rhetorical questions. How do you think social media became popular? How did tiktok, snapchat, facebook, instagram become popular? Even yikyak became popular because they targeted teens. Why has so much advertising been targeted to teenagers for decades now? Hell, how did onlyfans become popular? All these companies have massive incentives to target teenagers.
So your stance of these porn companies not targeting teenagers is just being willfully obtuse.
Targeting them has a lower return than targeting people who are of age.