Comment by jongjong

This is almost always the case. It's one of the frustrating things about the software industry; because everything is much more complicated than the customer is able to comprehend, a software company can promise anything and the customer can't actually verify.

So any software company/project which actually took the time and effort to fully handle the enormous complexity, they can't sell themselves based on that fact because every other company (who didn't invest the effort) is also claiming it and the customer has no mechanism to verify the claims until some major rare event occurs.

And most of the effort is required precisely to handle those 1% of rare situations.