Your above average talent gets trusted with high stakes, client-visible scenarios like new business development, RFP pitches, and high-visibility fire fighting. The roles tend to be a combination of subject matter expertise, solutions architect, client management, and sales.
Once you have a contract in hand, theoretically the engagement is structured at that point. It no longer needs the independent competence of members of your A Team, but rather competent project/program management, client/engagement management, and execution resources.
That's the stage where a lot of problems get introduced, and it's not always a result of cost cutting or profitability measures. A lot of it comes down to operational competency (both for the agency and the client), as well as the structure of the contract itself.
The biggest thing I've learned in my time consulting is what to do (and not do) when structuring a contract for a consulting/outsourcing engagement. Everything else cascades from there.