I am an IT Manager, and the most senior IT person in my current (and previous) company, so I think I can speak for many of us.
By and large IT is considered by most non-IT people some kind of voodoo or black magic. And most people are afraid of what they don't understand. Top execs and directors are no exception to that.
I was lucky enough to have had one boss, who admitted to that and we focused our relationship on the non-technical side, which worked brilliantly, because he took the time to discuss questions of innovation, risk, benefits and expense. With other superiors I have had less luck, and often the lack of understanding results in situations where there is also no will to spend any time on these discussions, which just aggravates the situation.
And when that happens, I find myself in an almost impossible situation. On the one hand I have all these ideas coming out of the team, some of which are great and others are not so great, but still good (and yes, there are some stinkers, too). On the other hand I have a boss who only sees IT as an expense, and does not even want to enter into a conversation about possible benefits of new business systems or major revamps. It's no surprise that my team gets disappointed. However, I can tell you, that doesn't even come close to the frustrations I have to deal with myself.

You could, of course, argue that this is also my fault, that I should be able to translate the techno-babble into business cases. And I presume that's partially true. But as always, it takes two to tango.