I agree costs must be managed, and that is why I think a grant program would help local communities decide if this was a priority. I have a customer who woke up in the yard with a washing machine on them after a tornado, and her son had permanent brain damage. I was out on Navarre Beach with no basement or saferoom when about 8 years ago a tornado jumped over us and caused about a million dollars damage to retail on 98. I got warning but as my wife and I got under some stairs....we felt incredibly exposed.
I built two homes where I took the front stoop of the house and built a hollowed out stoop with concrete walls and put a steel door to enter that space below the stoop. It really only cost me about a thousand more, and the cool part was because it was flush with the basement wall, I built a bookcase and put wheels on the bookcase, and we had a hidden room where my wife and kids could go during a storm or a threat at the front door. You would roll the bookcase away, open the steel door, turn on the light, roll the bookcase back, and then lock the steel door. The cell phones actually worked, and I had neighbors and people begin copying my design. Normally the concrete walls are about four feet, and then they are backfilled with gravel.....all I did was pour 8 foot walls on the stoop, and left an opening in the basement foundation, and then suspended the concrete stoop portion using steel panels. It would have taken a direct bomb hit to hurt the occupants, and even in a fire, the door had a two hour burn rating and was air tight. I put a inch conduit to the outside for air.