Not sure about these increases, but livable structure below the 100 year flood line will trigger a huge insurance increase. Fully elevated homes are done that way because otherwise insurance costs would be prohibitive. Other building methods and materials (like HardiPlank) also cut insurance costs.

Do you mean this?

https://www.jameshardie.com/products/hardieplank-lap-siding

I don't see how this adds structural support.

Properly installed HardiePlank and similiar siding is substantialy more durable than vinyl siding. Brick, stone, and other siding can be even stronger.

Ah, okay, brick is the standard in my area so I was confused.

It's not structural but durability. It's effectively concrete siding and holds up well.

Aren't stilts actually worse for a direct hurricane hit? They are great for flooding but terrible for hurricanes.

Some kind of underground waterproof bunker is probably the safest, but not sure those are going to be real popular.

(I meant that more as an example to follow OP's comment. I'm sure it would have to do with roofing material and other things structural in a hurricane zone.)

I think the concept is to build houses resilient enough to avoid storm and flood insurance altogether.