I've always said that 2 smart people can get way more done than an army of consultants in a shorter amount of time. (for the record, I'm an ex-consultant)

But this is business and this is why these companies make as much money as they do. When you are in charge of such a project and your ass is on the line who better to blame than a large Fortune 500 type of company (i.e. Accenture, Deloitte, IBM, etc). You can't get fired for failing a project with a vendor that is considered the "best" but you can for using "Jim's Custom Development Shack".