California has a 'public option' that works fine

Some excerpts:

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In 1911, California and a number of other states passed the nation's first workers' compensation laws, aimed at ensuring medical care and lost wages for injured workers. ...
By 1914, Washington, Oregon, Nevada and Wyoming banned private workers' comp insurers, creating state-run "single-payer" monopolies instead. Today, 15 states have such monopolies. California and the other states formed not-for-profit entities to compete with private insurers. ... Insurers hated the idea. ...
Competition from the fund spurred the private insurers to slash rates. One company cut rates by 30 percent. Others offered their customers free service for a month or similar enticements. Several small insurers could not keep pace and went out of business.
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But after a while, the State Fund and the private insurers found they could coexist. The State Fund attracted mom-and-pop firms too small to merit the attention of the major insurers, as well as high-risk occupations such as roofing or welding. The private insurers sought out larger employers, which allowed them to offer relatively low rates through economies of scale. ...
Around 2000, as a deadly price war between private insurers forced two dozen firms into bankruptcy, the State Fund took on their clients. In 2003, as rates among the surviving insurers skyrocketed, the fund briefly held 52 percent of the market as it took on businesses that could no longer afford the private policies. The fund is now back to historical norms, with about $22 billion in assets. ...
There are now more than 50 private insurers in California, holding 80 percent of the market.