Interesting question. Theoretically, no, because ideas are a dime a dozen, and there's no "one true way" to solve a design problem. But I think what you'd run into over time, which may be parallel to the man-month myth, is a higher-order approximation of groupthink. Meaning - "Let's apply this interaction pattern to solve this class of problem because we've done it before," repeated ad-nauseam. This will actually result in that parallel of the man-month myth - "solutions" (note the quotes) will be churned out at an increasing velocity, like a giant rubber stamp factory. The big difference is obviously ideas are much easier to create and document than software is to build. I don't think this is a result of the User Centered Design process, however. I think it's a result of the oversimplification of the interaction design sub-process, coupled with the broad lack of interest in the business improvement part of the process.

The problem with design studios this large, and operating on this consultatory premise, is that they will never get to influence the business "why" of solving a problem - they will always be handed a brief, and will always have their solution bounded by decisions made prior to their involvement. They are compelled to do work on what someone else has determined to be the problem, not to uncover the problem themselves and work outwardly from there.

You actually see this all the time in finance - there are entire companies built around the idea of churning out datagrid UIs to banks that don't ever stop to consider the real underlying conditions of why a process is the way it is, or have the opportunity to change it. It just results in a lot of same-same being generated over and over again, and it's easy money for consulting groups to get into the biz - just buy a small (or several) design shop and start billing yourself as being in tune with "UX." Deloitte, KPMG, MarkIt On Demand, EY, PWC, Accenture, EMC, and a bunch of other places are doing it just that way.