FYI, my firm represented several power marketers in the California crisis, and I testified for one of them; my take on the subject is probably different than the official histories. ;-)
California started with a seriously flawed wholesale market design, which my colleagues saw before they were implemented; the market design, despite these visible flaws, had features that PG&E and SCE really liked, so that's what went in. Enron employees (and others) saw these flaws and drove the proverbial Mack truck through them.
What really compounded the damage, though, was California's decision to enter into long-term contracts at the top of the crisis, purportedly to spur new investment that would introduce competition. The politicos assigned this task to a complete neophyte, who signed billions of dollars of ill-considered contracts, thus prolonging the economic impacts that should have lasted no more than six months to a period of many years. This also laid the groundwork for utilities to return to the business of long-term procurement and, in some cases, direct ownership of new generation -- reversing the course towards market-tested efficiencies.
The retail market closure is a different matter. As soon as you get utilities entering into over-priced contracts, there is an incentive for customers to escape to market-priced alternatives. If the CPUC allowed that to occur, it would stick the utilities with the above-market cost of those contracts with no customers to pay, bankrupting them. Thus, you lucky Californians are held captive to your utilities instead of being provided the retail market choice most Americans have.
Sorry if this sounds bitter, but it's a really sad tale of the worst of both worlds: neither a well-regulated monopoly nor an efficient competitive market.