Depends what they mean by "system". I read that as 200 applications, rather than interpreting as system = device/server.
In your interpretation, I'd completely agree, 200 devices/resources is not at all OTT.
But 200 applications, each with their own reliance on supporting systems and infrastructure, each application having their own data flows... I wouldn't fancy detailing that data model (unless it was for a fee, mind).