Client pay for predictably mediocre. It's a scale: pay $X and get Y% probability of the project being done by D date. Of course they don't even get that; in practice, Accenture are as unpredictable as any large-scale software development effort. So rather than mediocre yet safe, you get mediocre, and late, and over budget. LOLZ on you! Or on your poor shareholders/taxpayers more like.
When I dealt with Accenture (back when they were Anderson Consulting), they were quite predictable - always late, always over budget, and always producing an unmaintainable mess.
The developers were good or bad in about the same percentages as other companies, but the management structure was designed to suck money out of the client. Work product was secondary (or, whatever) and it showed.
