We've queued up a 5 minute Darwin Talk from EvolveLaw that presents an interesting question about law firms. The premise is that law firms typically exist for 4 reasons:

administration & support
physical location with means of production
knowledge, mentoring & collegiality
provide a steady stream of work

In the video, Mark Lassiter suggests that the main reason law firms currently exist is the last bullet point - to provide steady work to lawyers. Think of it as a mechanism to funnel work to lawyers. We've thought about that idea for a while too. But I think he explains it really, really well in less than 5 minutes. Take a look.

Maybe think of it in terms of how movies are made: get a director, a writer, actors, film crew, etc.