Can corporate tax loss carryforward function like a sort of insurance policy?
The structure of the tax ladder is such that the marginal tax rates keep increasing. The upshot is that if you earn more, your net earning (after taxes) will never be lower. So a company with a good year will always be better off compared to a company with a bad year, holding everything else equal. In this sense, tax does not provide advantage to companies with a bad year.

Your idea of "insurance policy" would be most closely related to the concept of automatic stabilizer. But this concept talks about the macro picture of the entire economy, so I'm not sure if it's wise to link the two together.