I've had a similar frustration with review replies. Though I've got another frustration of my own:
Something I noticed was that developer replies don't always seem to be visible to visitors (try visiting your extension's page via a different account or browser profile, and refresh the page a couple of times).
In my case, I received a valid negative review. I replied and edited it with a live receipt of things like rolling back the release, submitting a new version for review, and steps forward.
However, without the reply being visible to some visitors, it could end up looking like I never addressed the issue?? Especially since in my case it had something to do with permissions.