They broke their respective glass ceiling with the help of EO 11246, after they toiled to acquire sufficient political clout to induce politicians to help them. Both private and government studies have shown EO 11246’s effectiveness for blacks and women. (See, e.g., Leonard, Jonathan, 1984. “The Impact of Affirmative Action Regulation and Equal Employment Law on Black Employment” Journal of Economic Perspective .4:47-64.)
To see evidence that the glass ceiling is much worse for Asian Americans than for blacks, women, or any other group: http://www.80-20initiative.net/news/preselect2008_attachmentA.asp.