My point is that teen pregnancy very much does have a solution that has empirically worked quite well at preventing it when it's actually practiced (i.e. high quality sex education and ample access to contraceptives), and pushing abstinence as a solution has demonstrably caused teen pregnancy rates in increase whenever it's used as a replacement for that; the only actual impetus for abstinence as a "solution" is ideological. I think teen pregnancy literally would be a solved problem (with instances being essentially a rounding error) in a society embracing what we actually have proven works well at preventing it; I've never seen any similarly successful mechanism at preventing injuries or deaths in automobile accidents be rejected by a society for ideological reasons.

Trying to handwave away the things we know work to prevent teen pregnancy as "just be careful" feels overly reductive, because it's way easier to do correctly than managing to drive without ever having an accident.