Publicly traded corporations are at something of an impasse in the U.S. Their numbers are shrinking: from 7,507 in 1997 to not much more than 3,500 now. Their ranks are getting top-heavy, with most profits and cash flow accruing to a shrinking group of giants:
That chart data is from a new(ish) paper, "Is the American Public Corporation in Trouble?" by finance professors Kathleen Kahle of the University of Arizona and Rene M. Stulz of Ohio State University. Their conclusion: Yeah, it is.