THAT'S WHY!
I see. There is the easy way, and the samurai way. The easy way is to ask the exchanges politely to publish compounded data.
The samurai way cannot be discussed in public, plus the samurai would keep the answer for themselves.
I kind of think that they can't disclose that information publicly.
Why not? They disclose lots of other things. Publishing a current total of funds held would in no way expose personal information on individuals. Also, publishing makes it public, so there is no unfair advantage to anyone.
Hey if they ever do publish a chart of incoming FIAT and outgoing transfer totals on a daily/hourly basis. Let me know. That information would be useful in determining overall market direction.