Honestly, I'm not sure you did. On a 2012 mac pro I think the ram is still fairly accessible, so take off one 8Gb bar away, reboot, and even if you loose dual chan, you'll see that you will have no trouble.
So you're in a very specific situation here. It happens. But it's rare.
Well... I have no idea where to start here to be honest. You're not 100% wrong, but your are missing more than half of the picture here, and you are misleading, and your conclusion is totally false. And saying that you teach that is making me worried :s
You are missing more than half of the picture because before hitting the Swap there is plenty of process depending on programs and OS itself that will make you avoid hitting that threshold. Windows and Mac are handling it differently, and programs are handling things differently as well, so I'll only be synthesizing very briefly and simply here as I don't have 2 hours to write all of those things down (and I don't wanna look presumptuous, or pretentious here )
First, on programs themselves : some are pretty good at it, some are not (browsers and most videos games are good at it for example). What's happening is that programs will allocate as much as data they can in the ram -in case- they need it, even if that data is not used for long periods of time, and when we start to hit the max capability of ram, we'll see that a lot of the data stored that is not used will simply be replaced. Programs using Java or the .Net platform tend to do that automatically via the Garbage Collector, when hard coded program using C++ (for example), need to be implemented manually.
Also the OS themselves do the same kind of things, under different names, during different period of times (Windows being a but more efficient at that than Mac sometimes, and sometimes it's the opposite - Mac programs when using Cocoa API typically).
And here I didn't talk about more optimization that exist (and that I'm not aware of all of them), including Ram compression.
So basically, you hit hard bottom of ram when you have "IN USE" data that fill ALL of it, and not only just or a mix of "pre-load data in case of" anymore. And it's rare to reach that. You gave an example when you run your DSP algorithm because everything stored is actually "In Use". And it's also why Servers tend to need more ram, because they tend to store mostly In-Use data.
(and that's also why Chrome is topically working the same when you have 4gb, 8gb our 16gb, whatever number of tabs you got open -excluding Flash opened tabs if badly implemented but for other reasons I'm not gonna explain-).
So NO, having more Ram is not always good, stop spreading false info.
('cause of course, hopefully, you don't hit the Swap each time your ram "seems" filled).
Personally, I doubt it, but well, maybe, we never know