Kids still get to walk with cars around, ride bikes, drive motorcycles usually a few years before majority, they also ride cars and are usually familiar with how they work way before driving.
I'm actually of the option we should have a smartphone category/setup at the same positioning as bikes are to cars, it would even benefit adults the same way not everyone wants a car.
We do, they're called regular cellphones. They can be used to make phone calls and even to send text messages, but they can't be used to access social media hellscapes.
Phone calls are for emergencies at this point. If it's not it's spam. Then Apple ruined SMS ( except for the US apparently?), nobody wants to gamble whether a message will reach a phone or the iPad sitting in a drawer still associated with the phone number.
So social things, like communicating with people, happens on social apps.
Kids also would be better with map apps, GPS, electronic payments and auto-charging bus/train pass if you expect them to have any independence.
All in all, kids should be the last ones IMHO to get real dumb phones. We might as well give them pagers if that's what we're going for.
I'm actually of the option we should have a smartphone category/setup at the same positioning as bikes are to cars, it would even benefit adults the same way not everyone wants a car.