Yes, the total destruction zone will probably not extend more then 10-15 miles max in a cat5. Land features will also affect this. I suspect some of the bayous will all for the longer run versus the shorter becuase of less land mass friction. However, it does take almost perfect conditions to maintain a 4 or 5. Cat 3 can be maintained for a much longer distance. While not as catastrophic by a exponential scale, I can assure you that a cat 3 can cause major damage. Have a couple of condemned house in my neighborhood still from one.

EDIT: Posted before I saw margie's edit that covered this. Can be deleted.