Investing a lot of time and trying really hard is not the same as adding a lot of value. If your users don't find value in your documentation, saying "But we spent a lot of time on it!" doesn't really change anything.
And, to be clear, I have no idea if the person you're responding to's criticism is valid. But I also know that your response does not negate their criticism at all.
And, to be clear, I have no idea if the person you're responding to's criticism is valid. But I also know that your response does not negate their criticism at all.