I am with you on the warranties, that is real easy to believe. They are working on the odds, plain and simple.
The test of the etch under the epoxy says a lot. But how in the world could you say a salt spray test on bare anything is a subjective test? Bare etch primer? It isn't meant or recommended to be used that way. It is like testing paint applied to a block of ice, when it fails you can't say the paint is of poor quality.
Have you done tests with these products applied as recommended with paint over them to protect it?