This is a district level (or perhaps state level) decision. I live in San Jose and have two elementary age kids in the public school system. Like the top commenter noted, this district is hugely variable in terms of socio-economic demographics, and the district policy prevents them from starting any online system that doesn't work for all students. Being a fairly poor district, not all kids have computers at home, and the schools mostly don't issue devices, either. As a result, teachers who are trying to provide any sort of continuity are entirely on their own, and in violation of policy.

We've been seeing a lot of Zoom + Classdojo + Google Classroom ... and for the younger kids, things like Achieve 3000, multiplication.com, etc., that they were already using in school.