Why is it so much cheaper to live in Riverside county rather than Los Angeles county?

I understand that Los Angeles is famous, and everyone wants to live there, but is that the only reason? I'm asking because I currently live in a 3 bedroom 1 story house in a very nice part of Long Beach, and our house is worth $500,000; although, in Riverside county (cities like Chino, Corona, Ontario, Riverside, etc.) you can get even a beautiful 7 bedroom home in a private community for even $400,000. So, my dad is looking into moving to Corona in a slightly larger home for around $300,000, so he will have a smaller house payment. Anyways, can someone please tell me what it is like there and if it is even worth leaving if we end up getting a bigger house (which me need), which will be much cheaper, and also in a gated community?