This gets to the fundamental question of “What is the purpose of government?” At its most minimal, basic level, most would say that government should help ensure public safety. That is why we have police, fire departments, departments of health, building codes, licensing for jobs that could impact public safety, car inspections, OSHA, pollution laws, waste water laws, etc, etc….. Trump continually says he needs to take extreme measures to protect public safety from all those dangerous immigrants, so he needs a gajillion dollars to do it. It all costs something to protect people.
Your question suggests that people know the risk levels when they buy property. That is a dumb assumption as most are clueless, and that is why government should take a role in managing public risk from such events. Governments all over do that already with flood plain management projects to minimize flood impacts. Another issue is that flood prone areas are typically owned by the poor in society so the wealthy may not see spending government resources on those areas as a priority. In 2024 alone, extreme weather caused 568 deaths in the US. That is why, prior to Trump, the Defense Department had for many years considered climate change to be a national threat. If 568 people died from terrorists, you know the government would spend a bajillion dollars fighting the enemy.
The problem in TX seems to be that their government is in the pockets of the fossil fuel industry and any proposals to address and mitigate future climate impacts are a taboo subject, lest government has to raise taxes.