If anything, I think a really failed experiment is one that makes you think you've learned something that is in fact wrong, which is the result of flaws in the experiment that you never become aware of.

I think Ferguson would call those "results," and from those you would have learned about performing experiments, not about the original hypothesis you were interested in.

Ferguson's proposed new language is a downgrade. Being unable to identify something as a failure when the outcome sucks is fatalism and not particularly useful.