My humble view: at high level in large firms, everything is politics. Even assuming high-level managers with the common good in mind, someone will sponsor with millions of dollars 10 useless but good-looking and inoffensive projects, just so they have the political capital to start one that is useful but may ruffle feathers. Your direct subordinate's failure is _your_ failure, and that will set back your ambitions. Peers turning against peers is frowned upon, for the same reason. And besides, you know them, maybe you even like them, the lower-level people are just anonymous faces, it's emotionally much easier.

And assuming they have the common good in mind is of course ridiculous.