Right, we don't know what the long-term usage of these composites in commercial aircraft will result in, in terms of service-life. I'm sure Boeing have their projections, and I'm sure they're optimistic. I think the larger firms will sell off their aging stock to developing nations as they approach end of life. Those nations might be inclined to extend the life of their air frames past original specifications due to economic reasons.

We know the FAA rubber-stamps whatever Boeing claims at this point, so don't expect regulators from keeping your plastic plane from disintegrating mid-flight.