Internal investigations are a lucrative practice area. When a company hires a firm to do an internal investigation, something has gone sideways, and companies are willing to pay top dollar to fix things.
Look at it this way. Another way this situation could have gone down is that Apple could have conducted an internal investigation of its antitrust practices before the DOJ's action against them, in order to show that they were proactively and voluntarily addressing the problems. If Apple had hired a private firm to do the investigation, $1,000+/hour would not be an extraordinary fee for the lead partner on the matter.
Look at it this way. Another way this situation could have gone down is that Apple could have conducted an internal investigation of its antitrust practices before the DOJ's action against them, in order to show that they were proactively and voluntarily addressing the problems. If Apple had hired a private firm to do the investigation, $1,000+/hour would not be an extraordinary fee for the lead partner on the matter.