There's no doubt in me that whites will break 10 seconds, what will be very hard to reverse from the caste system in sports is the health and durability of white athletes.
I have seen many prominent white athletes in many sports (especially Baseball, Football, and Basketball) who suffer near constant injuries that shorten their careers and impacts on their respective sports.
Jason Sehorn, was a very good cornerback, but he would have been one of the best had it not been for injuries. Chris Mullin, was a very good player, like Sehorn, injuries got the better of him. Mark McGwire, should have crossed 600+ home runs, but injuries prevented him from ever reaching that elite mark.
The White sprinters of this generation, despite their great potential to break 10 seconds, are bound to suffer various injuries at some point. This is a predicament caste-lovers are hoping for, 'cause an injury seems unthinkable to Usain Bolt at this moment.
Another dilemma white athletes face is all the illegal performance drug stuffs. Guys like McGwire, Armstrong, Landis, Kenteris...etc., have all been subject to illegal drug scrutinies. It really pains me to post this stuff, but it's a really for whites in sports right now.