Not many companies offer flood coverage up to policy limits. It's mainly the HNW carriers such as Chubb, PURE, etc. You can sometimes buy excess flood (like an umbrella) that sits above the standard 250/100 flood policy that the NFIP offers, either thru a HNW carrier or a wholesale/surplus lines avenue.
The thinking was you could have a foot of water on the bottom floor of a home but once the water recedes you can clean shit up, replace flooring and whatever was damaged. In instances like this, or New Orleans in Katrina, the whole home is destroyed. (Hurricanes are probably a bad example because then you get into arguments over whether the primary damage was the force of the wind or the rising water.)
Oh, and flood insurance can be very expensive depending on where it's located in the flood maps. If you're not a primary flood zone, they're pretty cheap $500 or so annually. I won't tell anybody they don't need a flood policy any more. There ain't a place on Earth that can't flood given certain situations.