Yea I think they make more money by having several smaller conventions at facilities that are already paid off than a few very large ones. Most often it seemed that the larger venues were under utilized anyways.
Our last International that I attended at Ford Field in Detroit, Mi was pathetic. Sooo many empty seats. It was hard to miss.
I think too that all the older people can’t handle all the “too do” that comes with a large venue. It’s just way too hard on them physically.