That’s the inevitable consequence of the local decisions that have made it dangerous or impossible to walk to school. Many school districts then see an opportunity to save money by charging families to ride the bus.

Ergo, massive traffic jams of parents individually driving kids to school.

The logical followup would be to subsequently charge parents to use the pickup areas and lower/subsidize the bussing costs.

Bussing in the USA was a civil rights innovation to integrate schools. At the time neighborhoods were still racially segregated, so neighborhood schools were overwhelmingly the race of whatever the local neighborhood was. The only way to have integrated schools was to send many kids to a school in a different neighborhood, hence bussing.

That’s distinct from just having school buses. Most school bus service does not exist to desegregate school districts.

You are correct. But Seattle's history with desegregation bussing had a major impact on the nature of the schools in Seattle today. It was very common for students to spend a total of 90 minutes each day being bussed across town rather than walking 15 minutes to their closest school. It gave birth to a thriving ecosystem of private schools that still dominates the social fabric of the city today. Over 25% of all students in Seattle are in private schools, with that figure being much higher in the wealthier North Seattle neighborhoods.

The suburban schools I’m thinking of are perfectly walkable.

There’s also ample bussing.

The parents just want to pick their kids up.