I've been looking for something like this for a long time. Thank you for sharing! I especially like point number 2. It reduces the amount of meetings I have SIGNIFICANTLY.
We're talking about a meeting that wasn't a recurring event, so at least the person setting it up had an intention of getting something out of it. If there's no output, it's more productive to understand why it failed than to stick to or try to enforce a random guideline.
Perhaps there's just too many conflicting interests and someone has to take the lead. Perhaps nobody actually knew what was going on and the whole meeting was spent getting up to speed (funnily enough, prepared agendas often won't help for fundamental misunderstandings). Perhaps there was no output to expect in the first place and the person setting up the meeting lost their way.
You'll improve/reduce meetings by looking back at these failed attempts and act on the findings. If your team can't do that, they won't be in a position to properly understand and follow a guideline either IMHO.