Formal type of dress for public events and public gatherings was commonplace into the 1960s. Any viewing of older video coverage illustrates that. With the rise of consumerism and the great cultural changes that occurred in the 1960s and 1970s, dress requirements became more casual. Also , you started to see the development of team sports merchandise clothes which really has exploded over the last 3 or 4 decades. As someone who worked in the corporate environment for 40 + years where suits were required until maybe 15 years ago, I appreciate the more relaxed style of dress. I dont care for wearing suits/ties etc.