Poverty. The answer is always poverty. Evacuation is not free and never has been.
Currently sitting in the Tampa Bay area while a category 5+ hurricane comes barreling at me. I'm in flood zone D next to E so I shouldn't have any issues there. In a building that is solid brick/cinderblock construction, built like a bunker. Don't worry about me. I got water, food, and enough fat to get me through the winter as they say.
The one thing I don't have is the hundreds or thousands of dollars it would take to drive 2+ states away and get a hotel for a week. I simply don't have it. Then you have all these people in places like Missouri or Montana posting this question about why people would not evacuate. We don't have the goddamn money. It's not hubris. We SHOULD evacuate. I don't see any of the people saying this offering up a spot on their couch. We should always evacuate... somewhere other than the house of the person who thinks we should, apparently.
This happened with me when Beryl struck my town. It’s a little easier to relocate here because the government hasn’t quite been able to penetrate the rural areas, which makes it easier to just abandon your home and leave without having to deal with any legal issues. But money will still play a part when you want to find a job in your new town and the nearby areas are pretty poor as well. You would need to spend more money to move up further north where people tend to be more elitist towards those from the more rural areas, especially if they lack money.
Most of us don’t want to deal with that hassle and so we took the hurricane head-on and dealt with the aftermath ourselves. The town still hasn’t fully recovered since then and I fear for the next round of hurricanes we’ll have to weather.