...resulting in 3 or more fatal crashes...
Two, actually.
...static fatigue test which should have shown up the flaws in the wing and nacelle design.
Not so.
Only dynamic testing would have shown the problem, and not just the usual flight test procedures for certification, either.
The L188 lead directly to the P3 program for the US Navy (and several other countries) so Lockheed definitely made a profit with the design.