They definitely should have made an announcement in the club if they were boarding a delayed flight. In most clubs they do. You could have also asked the club personnel at the front to make an announcement when boarding started if you were concerned about it.

If the reason for the delay was maintenance or ATC, there is a great deal of variability in the accuracy of the departure estimates. If it's late inbound aircraft or flight crew, they have a little more certainty on when the missing element will arrive - but even in those cases they can sometimes get backups. Most gate agents that announce delays will state to stay near the gate in case something changes.

I think you probably got more than your "fair" share in this case. I definitely think there is more they could have done in terms of changing the boards and making announcements in the club, but you still have to bear some of the blame. Which airport was this? If ATL I wouldn't expect much help from the club as they are pure chaos. Smaller locations are generally much better about these sorts of things.