I do not think that the success of Jackie Robinson West in the little league world will lead to more diversity in baseball. There have been many successful diverse men in baseball and one new person is not going to change how many children no matter their race will want to pursue baseball as a sport.
So the headlines are touting more diversity in baseball. Last time I checked baseball has a heavy minority presence. This question is somewhat convoluted in it's asking. The team was all minorities and good for them, but trickling into a heavier minority roster in baseball would mean Whites would have to be drafted more.
Major league baseball is by far the most diverse of the four major American sports leagues. It is unlikely that this will change any time soon and loss of diversity seems unlikely as well. Although exposure to youth leagues is great, I do not believe it will lead to major changes in the demographics of baseball.
Ms. West is an excellent ballplayer, but she is an exception to rule. The average 13 year old does not have the physical talent to play competitive baseball at that level. I do think that her success will make more girls aware of the value of sports and will lead to an increase in female softball players.