That's been my experience as well, but I think that's less due to management malice than it is a combination of a lack of understanding for what tenets are for (being useful decision facilitators rather than a blend proclamation of corporate mambo jumbo), and a lack of decisiveness. It's very amazonian to ask for both top quality, and shortest cost and delays at the same time. Since that is not physically achievable, resulting tenets are bland.

Note that the leadership principles are also a form of tenets, with their own internal contradictions that is waved away by a usual "it's a constructive tension".