Assuming this isn't a rhetorical question: San Diego, Davis, Irvine, and Santa Barbara all rank in the top 15 US public, top 50 US / top 200 global universities (USN&WR, THE, QS rankings) and have specific programs that are world class ( including the ones you mention--two UCSB professors won last year's Nobel in physics.

Though Berkeley and UCLA have the advantage of most all departments being top 10, "average school" is not a fair assessment for the rest.