To my knowledge, nobody has been allowed to play any of these games. So you can't say anything has been proven to work ok.
Tons of people have already been allowed to play AC:O on stadia. Go look up project stream.
So yes I absolutely can say this.
16.6ms is one frame of latency.
At 60 FPS. At 30 FPS one frame is 33.3 ms.
Even if you live next door to the data center, your internet connection is going to give you roughly 15-20ms latency. Plus the time the game takes to render on their machines, and then make it out to your display. By the time that all happens, you are looking at MANY frames of latency. It *WILL* be noticeable.
You are indeed looking at multiple frames of latency (5 on average with AC:O), but no this won't be noticeable since multiple frames of latency is completely normal for PC gaming (and even more so for console gaming). I understand that you clearly haven't looked into this, but it's not like this is hard to learn about. Just take a look at eurogamer link for actual measured latency numbers.
I never said you could do it with a potato. A good PC with a high refresh monitor is required. Check out blurbusters for examples if you only own a potato. 20ms is considered the threshold for presence in VR. IE when lag get noticeable. Typical and objectionable are different numbers and a lot more subjective.
I personally can tell when I have my PC setup wrong and I'm getting 30-50ms input lag. At 60hz 30-60ms is probably more normal given you have hardware capable of keeping up with 60hz. 150ms is just absurd. I've accidently left the post processing on my TV that gets it over 100ms and it feels like this weird swimming sensation where you are completely disconnected from the game.
The numbers I mentioned are not for completely normal gaming computers, not potatoes. I doubt that you can tell the difference on your PC between 20ms input lag on one hand and 30-50 ms on the other. Most likely you can tell the difference between 20ms ADDED input lag and 30-50ms (from display lag, network, whatever), but not 30-50 ms total input lag, since very very few games ever get that low.
If you can indeed tell a difference then you are very much in a tiny minority of extremely sensitive people. If so, then Stadia probably isn't for you, but I doubt Google cares, considering how tiny of a percentage people like you make up of the market.
VR is a completely different issue, since you are also moving your head (and thus activating your vestibular system), but that is not relevant for Stadia.
And these tests aren't entirely valid as they clearly state it was conducted on a Google connection. Since Google was in control of the tests, they would of course make sure it was going to be seen in the best light possible.
This doesn't appear to have made a significant difference though.
During project stream, they also tested latency on a home internet connection, and while they had slightly higher latency (179 ms versus 166 ms), the difference was small enough that it could probably be explained by the difference in software builds (project stream being a beta version), and not necessarily by any difference in internet connection.
It's also worth noting that Google has claimed that anyone using Stadia will never be more than 64km from the datacenter running the game, so if you are getting excessive network latency it's probably your ISP's fault not Stadias.
They use the most favorable, to them, choices.
PC 30fps 133ms
Stadia 166ms
That is 1 frame. 33ms @ 30fps.
That's not simply the most favorable choices, it's the most apples to apples choices. Stadia in that test was running at 30 fps, and as such the obvious apples to apples comparison would be PC at 30 fps also.
If 30FPS is their goal then this really isnt a gaming system anyways.
30 FPS was what Stadia was running at during the beta (project Stream), but their current goal is 60 FPS.
btw do you consider consoles running at 30 fps to not be gaming systems either?
So A frame is rendered every 16.66ms minimum if that's accurate. What is the PC doing for 62.34ms?.
https://www.anandtech.com/show/2803