California is the #1 state in total MLB players (duh, the huge populatino) AND the
#1 state in total MLB players per capita (13.21 per 1 million males).
California, without a doubt, is the epicenter of amateur baseball in the United States.
At the Major Metro-Area level withinin California's borders:
1) San Diego (36 players, 25.44 per 1 million males)
2) Stockton-Lodi (5 players, 17.75 per 1 million males)
3) Los Angeles-Orange County-Riverside (124 players, 15.27 per 1 million males)
4) Fresno (6 players, 13.06 per 1 million males)
5) Sacramento-Yolo (10 players, 11.35 per 1 million males)
6) San Francisco-Oakland-San Jose (32 players, 9.13 per 1 million males)
Pretty evident that So-Cal does baseball better than No-Cal. Here is a screen capture of a Google Earth file I created with the High Schools of every major league player geocoded. In the mapping program, all of the player information is entered and if you click on the dots, it zooms right into the high school. They definitely all look like pretty nice high schools. You will notice it is a very suburban pattern, just like Zestways pointed out (rich white schools, with Inglewood HS being the biggest exception). This is less true in other parts of the country, especially down South where the brothers do play ball.
I zoomed the Google Earth file into the LA Metro area and took a screen capture:
