Not a single one of the projects I worked on or was directly aware of, in 4 years, ever used a subcontractor.
That's anecdotal evidence, but it should clarify that though it no doubt happens (and happened more before there was a Solutions Workforce), it's by no means the norm to hire subcontractors to "do the real work".
I'm not talking about subcontractors. Most consultancies, including Accenture in my limited personal experience with them, staff up with new hires (preferably cheap new grads) whenever they get a new contract. When business slows down enough that people are lingering on the bench, they get fired. They are essentially high-end temp agencies.
True. That is the "up or out" model at work. The few that survive such attrition are partner material, meaning they can put up with the lifestyle, enjoy the role of digging through other peoples business, and have potential as sales people.
That's anecdotal evidence, but it should clarify that though it no doubt happens (and happened more before there was a Solutions Workforce), it's by no means the norm to hire subcontractors to "do the real work".