Not really that accessible everywhere. Even where legislation says it "should" be, local practice is inconsistent.
Plus, I saw my (very careful, responsible, sexually-active) friend go through enough "broken condom" panics in high school that I suspect condoms and birth control in general are less reliable than I was brought up to assume.
Thank goodness for the morning-after pill, at least.
You know what might be better birth control? Showing young men and women the gruesome details of childbirth (not just the screamer videos, but the actual realities - the bowel movements, episiotomies, months of discomfort before and after, etc.) plus the unsexiness of life as a broke teenaged parent trying to make rent while still longing for carefree youth.
I think as long as some teens have the abstract idea of "Oooh, a little baby all to my own!", it will still be tempting to think unplanned pregnancies are no big deal. It's not enough to just use a condom and hope for the best. There needs to be a PLAN.