Some people call it freedom, others call it letting the benighted stay benighted:
Government regulations mandating storm shelters, either public or private, are inconsistent. There are some regulations for apartment buildings, and some states, like Minnesota and Kansas, require that shelters be built near mobile home parks. Many areas, like Williamson County in Illinois, commandeer churches or schools to serve as voluntary shelters.
Alabama passed a law this year that requires shelters to be built into new schools. But cities do not require residents to build their own storm shelters.
Making federal assistance for public works projects contingent on mandating shelters, and providing federal grants for shelters, would be a good way to pump a few billion into the economy, as well as expand our manufacturing base (for prefab shelters). I doubt it will even be proposed, for the usual reasons, even though the frequency of severe weather might be on the rise due to global warming.