They really didnt really.

Should also note that Southern Cal is NOT part of the University of California system so using them in your example would give a false impression, they are a private school and do not answer to the state.

They are just REALLY big as a state, and thus could invest a lot into the program, and take advantage of multiple large growing metro areas to boost the schools profiles. Many other states simply kept the state university system focused on one flagship campus, and it has paid off for them.

Texas ( the UT system has the 3rd largest Endowment of any schools in the US at 3X's the CA system, with the separate Texas A&M system also being larger by itself), Pennsylvania, North Carolina and Ohio are all good examples. The state that probably comes closest is New York with multiple top schools in the SUNY network, again many taking advantage of the wealth and focus of NYC and the other major metros.