Similar stories exist about many other large and small ballroom venues.
Several nights a week... 800 guests... Have you ever counted so many dancers at a ballroom event? I wonder what led to demise of ballroom dancing from mid-20th century to now.
Perhaps the most important was and is the increasing availability and improving quality of other types of entertainment. Even television is much better now. Add wide availability of excellent music, Facebook, online dating, online this and that, air-conditioned gyms, affordable cruises... Most of these was not available fifty years ago.
Also fragmentation of the business played a role. Secluded Arthur Murray studios, joyless and barely breathing small studios, more than four national and international organizations each with its agenda and curriculum, American vs. International, on1 vs. on2 - all fragmented the community. The role of the ballroom community in its demise cannot be denied.