The cynic in me thinks it has to do with power projection and the economy.
The less cynical part of me wonders if it’s related to a cognitive bias that over-weights threats from rival “tribes” and the need to ensure stability
Especially for the states (and representatives) that the ice storm is 100 year. Dams fail, and when they fail, they don't affect the people that didn't want to live near a dam.
It seems like we’re just really bad at thinking clearly about low probability / high severity risks
The dam flooding isn't random, its an unfrequent event that will occur so it is something we should prepare for.
CEOs are graded quarter-to-quarter and politicians every 2-4 years. Low probability events (plane crashes, infrastructure failures, etc.) may not ever happen during their tenure, incentivizing them to defund preparing for them to favor other programs, understanding full well they’re bound to occur