A paradox of specialization yet much more outside counsel

Why is it that the so-called generalist lawyers who support a business unit tend to use outside counsel more sparingly than do specialist lawyers, such as intellectual property or employment/labor lawyers, who turn to them frequently?

Wouldn’t it be expected that if you’re a specialist, you should know your area of the law and not need recourse to a law firm partner? The Greek chorus answers: “Silly boy, specialty areas of law have arcane, fast-moving, and sophisticated questions, unlike the general practitioners who recommend the legal equivalent of an aspirin and a night’s rest.”

Many departments have a low-level tension between the heads of business-unit lawyers and specialists. Say the heads, “Why should we call in our specialists if they are merely conduits to expensive outside counsel?”