The study seems to be based on public (i.e. large and mature) companies, which are most likely to have 17 layer deep bureaucracies, and nobody actually listens

The study seems to be based on public (i.e. large and mature) companies, which are most likely to have 17 layer deep bureaucracies, and nobody actually listens to suggestions from below the top 2 layers. And top executives tend towards sociopathy. Conceivably this last characteristic leads to an additional confounding factor - those executives generally have influence over when and how many options to be granted, and would be best positioned to use insider information to put as many of their options in the money as possible. A good example would be the whole options-backdating scandal a while back. The conclusion seems valid, but just reflects the reality of large public companies.