I'd love to know where that money at IEEE and ACM is going. The annual reports don't make it at all clear, unfortunately. Obviously, there are for-profit publishers where the money is simply going to huge profit margins. But that's not the case for professional societies.
One thing I noticed when I had to sign up to ACM for a conference a few years ago was that I got harangued by sales-people from ACM for months afterwards, trying to get me on a call to have me buy more expensive memberships. It wasn't an automated system - it was an actual person, trying to get me onto an actual phone call with them. It occurred to me at the time that that must be very expensive, yet it's still a profitable thing for them to do - so there's clearly a lot of money changing hands...
I don't think this is a good sign. Perhaps the professional societies can openly publish a full breakdown of what they're spending money on?