US suburbia has a higher density than the German countryside, having to travel 24km is nuts. That'd be defensible if you live in a tiny settlement 24km from a place with more than two dozen houses -- I'm sure those exist in the US but suburbia isn't that.

How many pupils were there at your school? My state has 106240 pupils in 393 primary schools, that's an average of 270. Minimum size under ordinary circumstances is 80, the smallest is on Nordstrandischmoor: An island, 18 inhabitants, five families, one school, one teacher, two students, here it is. That's because we don't do boarding in primary education so there's a maximum tolerable commute time/distance, once those kids are old enough they'll spend Monday through Friday on the mainland.

If your system insists that a school have at least 2k students or such then, yes, of course, walking to school will be an impossibility for most. Fix your school sizes and like 99% of students will be able to walk or bike, use buses or minivans or whatnot for the rest we do that too (not really possible in Nordstrandischmoor, thing doesn't even have a ferry but a rail link that's only usable when the tide is low).

And no it wasn't my school it was my Kindergarten, which wasn't, by a long shot, the closest to home it was the one my parents chose. I mentioned it to say that biking 3.5km is something a 4yold can do, physically, without any issue at all really.