More than 40 years after women began pouring into the workplace, only a handful have made it all the way to the top of corporate America. The percentage of chief executives of Fortune 500 companies who are women just passed 6 percent, creeping up (and occasionally dropping back) at a glacial pace. Why don’t more women get that No. 1 job? Consider the experiences of the people who know best: Women who were in the running to become No. 1, but didn’t quite make it. The women who had to stop at No. 2.