I think you're slightly taking my example too pedantically. In any case...
> Is this just because non-IT managers don't trust what IT managers say?
Yes, but the non-IT managers are even more uninformed. Everyone at some point is to blame, unless you can point that blame outside of your organization. Imagine this conversation going all the way up to the CEO. "But Gartner said to stop supporting Blackberry" holds some good value to her.
> Non-IT managers blame IT managers for their use of analysts as a comfort blanket.
I'm sort of confused by this comment, is this a statement you're trying to make? Either way, as you said, the key decision maker is usually the non-IT managers (usually at VP level or higher).
> I realise there are analysts for all kinds of industry but I can't think of another example where analysts wield the kind of power that Gartner hold over the IT industry.
I don't know many other industries that (1) have so many solutions (2) available to them globally (3) at so many different price points (4) with such a complexity of features. Finance rings a bell, but the competition is much higher.
Some good comments about the woes of the analyst industry in big tech:
http://blog.softwareinsider.org/2013/08/09/personal-log-the-...