> haven't been on projects of this size, but with many of our customers a big issue is that the decisions are taken by people sufficiently high up in the organization that they don't know what's really going on, and without including key resources from lower levels to provide that insight.

This is my experience working in government IT. The people whose job it is to go to meetings and talk end up being the ones representing the businesses interest and the vendor ends up running circles around them because they aren't in any way qualified to talk about something technical.