✒ As someone who used to be on the advisory side of a Big Four firm, I agree that the audit and consulting skills are complementary and that the audit firms do rely on their advisory arms to provide expertise in tax and asset valuation for signing off companies accounts.

EY as the newly-separated audit firm will have to find ways to attract / retain tax and valuation experts required to check the books of companies, as top earners would likely want to remain in the advisory business where financial rewards are higher.