You have an asset. It's worth $1000. You borrow $1000 against it. The next year, after taxes and interest, you owe $1050. Meanwhile, the asset is now worth $1100. Your net worth has gone up and you have turned that appreciation into extra money to spend. You can do the same thing the next year, and your asset will be taxed as if it's worth $1010, and your net position is still in the black.
What you've perhaps missed, I think, is that property tax rates in CA don't scale with appreciation.