The problem with only having one standard is who gets to decide. I vote yoke as my USD Mistral, DAAM, RAM and single hoses all have them (not true, I have one DIN as well).
Now you vote DIN and the whole thing falls apart.
Standardization is more necessary as the situation dictates it for safety reasons ie. caves, wreck penetrations or deep/deco diving. However, Recreational divers get along just fine with yokes so to impose one standard would be artificial and limiting. The question in the title is too broad; diving is a large and varied activity and in that field, recreational divers make up, by far, the majority.
No need, no standard.