I was just wondering why there's a cap at all when hardware is factored out. Your guess makes sense. If true, this seems like a puff piece that doesn't really mean much technically.

"Windows 10 can hit 16.8 million terabytes of RAM courtesy of the 64-bit architecture"

There are certain kinds of internal timers in games that end up locked to a base tickrate; e.g. physics behaviors. While it's possible to allow adjustment of those rates in many cases, it comes at the price of lowering reproducability and behavioral stability.

As well, it's possible to make everything smooth by adding a buffer and interpolating, but then you've added a buffer, so you have latency.

So games that specify a hard cap are usually aiming for a low-latency experience where the highest framerate is the base tickrate for the gameplay, and lower framerates are sampling from within that data.

I think a lot of game engines really aren't that robust. Bethesda's engine is notorious for breaking the laws of physics when your FPS is above 60

One fun example from dark souls 2 on pc: If your FPS was set to 60 (from the consoles ~30fps) your weapons would degrade twice as fast apparently due to weapon durability loss being counted per frame that your weapon was in contact with a wall, floor, corpse, etc.