Racism is a very difficult thing to overcome.
I'm not convinced that Jackie's entrance into the MLB necessarily destroyed or truly harmed the chances of African-Americans getting a shot in the front offices or as managers. Because it allowed the opportunity for both sides to learn more about each other and break down those stereotypes and barriers that seem to come with the pigment of the skin. I would also like to add that there are still existing stereotypes. One would be that African-Americans can't manage or hold a front office job. Now, we know this isn't true.