So, maybe should be a different thread. I know these conventions are JW tradition. Probably, for two reasons, money maker, a time for releases of new light in bound book form, and a good hype for JWs to see in large groups. Teenagers and others could meet and work together in cafeterias and refreshment stands or 'clean' together. Most also did some door to door work in the mornings years ago at the conventions.
However, now, 'new light' can be internet downloaded, everyone can watch talks and cartoons/videos on their screens anyway, even the talks by their GB gods. Their packed lunches are uneventful.
Arenas are costly, when the WT has a new primary mission of building 'windowed' KHs.
Is it possible, for the WT to change this tradition only inviting a selected group to a big convention, video tape it back to the KHs for the peons to watch on TV. Guess not quite as dramatic, however, this is what big political rallys do and final sports games do and have no problem to carry on their fervor.
After all, all other religions have no problem carrying on their religion for decades without the cost of three convention sites to travel.
They could develop a once a yearly baptism program for qualified dunkies and their family. Having a big convention or assembly for a handful of baptisms, mostly of JW youth, is no longer dramatic for an expensive convention site.
Seems it could change some day. Obviosly, the WT has been downsizing how many days donventions are, Could downsize to one a year, for anuual baptism, etc.