What does it take for a risk to be insurable?

For a risk to be insurable, three conditions must be met: The risk must be diversifiable (over time, between people, between regions); It must be possible to model the risk, so that the insurance can be priced; It must be possible to model the moral hazard that arises from insuring the risk. There are risks today that are difficult to insure: Non-diversifiable (climate risks, pandemics); Difficult to model (pandemics, cyber risk); Insuring them leads to significant moral hazard (building in flood-prone areas, cybersecurity, etc.). So what should be done? Have the government provide insurance? Regulate or prevent rather than insure?