I wonder what the opportunity cost is for the various departments that get put into overdrive for any acquisition: business analysts doing number crunching, leg

I wonder what the opportunity cost is for the various departments that get put into overdrive for any acquisition: business analysts doing number crunching, legal doing legal, engineers doing various integrations, executives doing lunches. Countless (tens of?) thousands of hours of work before any productivity is yielded, and then when it finally is yielded its propped up by all kinds of dubious accounting to seem like more of a success then it probably was..