The irony is that this is probably going to exacerbate social injustice. Cupertino kids are going to be taking extracurricular math through RSM or Kumon in elementary school, and then the Cupertino school district (in the article) says that they have no intention to comply with the recommendations. SF kids aren't going to be exposed to algebra until 9th grade and then get a rude awakening in college when they realize all the cool courses have pre-reqs.
I've heard a good argument that algebra specifically should be moved the other way: teach it in elementary school, when kids are first exposed to arithmetic. There's a really natural progression from addition/subtraction/zero and multiplication/division/one to inverses and identities, and from addition/multiplication to distribution and associativity. My 3-year-old understands that if he has 5 raspberries on his fingers and he takes away one, he has 4, and then if he grabs another one and puts it on his finger, he has 5 again. Not a huge leap from there to the concept of equations, inverse operations, and solving for unknowns.