The best example of white kids being allowed to develop into top sprinters right now comes from Legacy High School in Bismarck, North Dakota. Although the school has but 1200 students, there are four boys on the track team who run sub-11 flat in the 100. Dylan McGlothlin has run 10.59 (and 21.12 and 47.75), Talen Farland 10.66 (and 21.42 and 49.40), Reece Snow 10.78 (and 21.76 and 51.2) and Nathan Mathern 10.81.
To have four sprinters of that quality at one high school in California, Texas, or Florida would be unusual but to have them at a high school in North Dakota, where the temperatures in March and April are rarely conducive to sprinting is extraordinary. Here we are at the end of the first week of May and right now in the middle of the day in Bismarck it's 53 degrees. Try sprinting in that!