I'd reword your French example a bit. I had the proverbial four years of high school French which I cared about and performed at probably about a median level (which is to say fairly well) of my high school subjects in general.

Especially in a pre-Web world though, absent pestering my parents to arrange some sort of exchange student situation--which would have gone well beyond my level of caring for any other subject and may or may not have been practical--I was probably never going to get to a high level of French proficiency without some sort of immersion.