Pfff, have you been to their offices and met the fookers?
The partners are like royalty who work on various projects by designating work to a team of lackeys, you wouldn't be able to make partner by working for Pentagram itself as you simply wouldn't have the responsibility and decision making ability that they require... this in my mind means that they're taking more from the industry than they're giving back?!
Sure they know their shit, but the self-riotousness would drive me potty! (Note that many partners leave after a few years as they "don't like the environment"... wtf?)