Frank Adamek has done what you suggest for years. That you don't notice it being done is a pretty bad sign about the idea. If you want to contribute, you should be trying to get people to use his system, rather than trying to introduce a new system. Or maybe you should suggest modifications. But the first step is knowing the current system.
I'm aware of Frank's posts to main. It came up during the last discussion about this idea. What I am suggesting is to remove the individual meetup threads from discussion, to clear up the clutter. In addition, the meetup cities would be right up there in the title (to respond to objections that having a single thread would result in reduced visibility). Instead of everyone submitting to discussion and then someone gathering up everything in main, everyone would simply submit to the person doing the coordinating. The reason I proposed myself as a volunteer was that I didn't know if Frank would be willing to do this, given that it would require daily correspondence with the people organizing the meetups.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.