The school has phones in every classroom as well as the admin offices. Before I had a cellphone and needed to let my parents know I was staying after school or going home with a friend, I just used a landline.

Breaking down on the side of the road is completely different than being without a cellphone in a building full of landlines. It's disingenuous to compare the two situations. Breaking down on the side of the road is pretty much the impetus for portable communication systems. A kid being able to just text mom that they need a ride after school is convenient but not really critical enough to justify letting kids have their phones on them all day long.