Well, most governments have had 'pro-family' politics that are against teen pregnancy; but in favour of getting married and raising children.
So they don't want to lower the sex-vs-age chart for all ages, they want to add a step function to it, so it's zero at age 19 but high at age 23.
Lowering the chart for all ages was never the goal, which might be why we've never seen politicians celebrating the current state as the successful delivery of their election promises.
Western European and East Asian developed economies share their largest economic problem going forwards: declining birth rates. I'm not convinced the policy goals of reducing teen birth rates has ever been that much of an actual policy goal, despite what election manifestos might proclaim
I don't think this can be blamed on porn though.
It's more that there's less of a need now, in Asian countries children are often a means of pension.
Also, women work more now. Life is extremely expensive even with two incomes.
And my personal reason, life is much more fulfilling without having to raise kids. I can do what I want, move where I want. I'm glad I never had any.
But hasn't that been an explicit policy goal of every government since at least 1950? Reducing teen sexual activity and especially teen pregnancy? According to elected officials, this is not just a good thing, this is the target.