Well, personally I would assume that if someone states that there is a problem with log backups failing now, they worked at some point, it would be really weird to assume failing now = never worked at all. Also, failure of log backups would not cause the log to grow if there had never ever been a full backup.

If the switch to simple did allow the log to be shrunk, then it implies that the lack of log backups was responsible for making the log grow, which would hence imply that the log was being retained for backups which only happens if there was a full backup at some point.

You can nitpick any question and argue about what's implied/meant/stated. It's why I never write QotD any longer.