I agree with you and you've explained your argument well. For applications that don't use much Vram, can get away with manipulating the pagefile, if it's only cpu that is doing the work. Once you add vram on top of that with demanding games today with gpus's with enormous vram capacities like your gpu, 8GB ram and even 16GB ram systems can easily be overwhelmed. In a gaming system, pagefile is unpredictable and i've been noticing a trend for sometime with massive pagefiles being created due to lack of ram to support the amount of data put into vram. Not all vram has to be used before data is swapped, depends how the game is coded. Several games of current like to page and coincidentally ever since gpu's went beyond 4GB vram.
Take a look at posts regarding stutters in games such as Devision, BF1, Ghost Recon and GTA5 with 8GB system memory with 4GB+ graphics cards. Now we have gpu's tripled in memory capacity and resolutions and details are increasing and as such 8GB ram is showing limits. Windows consumes 1~1.5GB for it's own which doesn't leave much for vram buffer. 16GB is becoming the new recommendation albeit too little too late. A correspondence with how vram is used for game data storage and when data is transferred to and from system memory then to pagefile if not enough ram. Even 16GB system memory will soon not be enough either with games to come, not with 8~12GB cards we have today.
If not enough system memory to buffer vram data (obviously faster choice vs hdd/ssd) giving way to cpu's own orientated workload then the next choice is storage.
Play one of the games i mentioned with 3 or so GB vram usage, we'll see if pagefile becomes a problem.