I think the analysis could be better.
First IMO it is silly to compare the peak players at at lunch with the lowest point on the daily cycle (perhaps its because he's Canadian and their peak time is ACCs low point). I'd suggest a fairer measure is comparing the 4200 peak at launch with the 800 peaks currently.
So having produced a fairer measure of the decline in concurrent users you then have to evaluate whether this decline is "normal" or not. A quick look at other racing titles indicates most newly released games suffer a marked decline in player numbers from launch. In the first month PC2 peak players dropped by 56%, F1 2018 dropped by 67% and Dirt Rally 2 dropped by 68%. However, ACC peak players dropping by 81% of launch peak in the first month does seem worse than you would expect.
Thirdly, I think one of ACCs bad points he missed is performance. If you have a good PC, ACC runs fine, but for those of us with older PCs (mine is 2.5 years old) it doesn't. To the point I can't race against 20 AI in ACC, while I can in other titles with at least 60 fps. If you read the comments below the video, performance comes up regularly so I am not alone.
My other issue with ACC is I don't find most of the cars as much fun to drive as they are in other sims. Clearly this is a far from universal view but equally I don't think I'm the only one.
With this in mind I find the proposed remedies somewhat irrelevant.