I've done some research around this for an upcoming book, and generally people who benefit from orchestrators are those that already have a solid regulation framework in place, where agents can get feedback quickly on most of the work, where deterministic guardrails (hooks/custom tools) are in place to keep the agents in their lane and where people invested a decent amount of time in making the agents run securely and know what they can or can't do (avoiding approval fatigue). you need all those prerequisites to make orchestration work well. once that's in place, running multiple agents in parallel doesn't burn man hours, but it can still burn a lot of tokens.
I wrote something recently on how we made the orchestration not burn that many tokens at all. With a few deterministic tools we got the token cost of orchestrated workflows down by 80%. Check out https://news.ycombinator.com/item?id=49587379