When I was first "coming in", early 1980s in our area, Southern New York State, USA, there were frequent " congregation gatherings". baseball games, picnics, parties of various kinds. These were open not just to baptized witnesses, but interested calls, studies, even "unbelieving mates" and other family members. I recall these as fun, encouraging events that really showed good will and unity.
As we entered the '90s however there began to be frequent Assembly, Convention, and meeting parts on "The Dangers of Large Gatherings" - too difficult to supervise, things could get out of control and something might happen that could bring 'reproach' on Jehovah's name. Gatherings should be small, by invitation only, and an elder should be asked to oversee things.
Almost immediately events of this kind began to dwindle and eventually stopped.
Knowing now how "Bethel-centric" the JW organization is, I would bet that something improper had happened at some event at one of the headquarters facilities, and thereafter, the entire worldwide congregation had to be "counseled and disciplined"..