You discovered that the wall behind your stucco has rotted out due to inproperly installed flashing by the builder who is no longer in business your insurance company says they will not cover this?

That would be correct in most all cases. Depends on the policy form and what state your home is in, but it would be very rare for this sort of incident to be something a homeowners policy would cover. Your homeowners policy is designed to cover common external casations, like fire, windstorm, etc. Wet rot is a commonly excluded condition under homeowners policies. This type of thing is what is generally considered to be homeowner maintenance. Remember that you insurance policy is not a maintenance contract. You could still have a cause of legal action against the builder (if an individual person(s)) that you can locate and the statute of limitations in your state does not interfere. It does not really matter whether this fellow is still in the business of building houses, he can still be held liable.