I see war thunder and world of warship adverts all the time. Are you saying that they are wasting money advertising and are too naive to realize that?
They were speaking of the ROI for HTC.
That doesn't mean that is the ROI for other companies.
A target has to like what they see in the ad to choose to click on it, and the they have to like trial enough to to subscribe.
I don't know what their click-through-rate was, but from the tone of the comments lets say 2%. He has stated he is running "around" %1 conversion from trial. Which could even mean below 1%, but lets say 1%. And most of those may not stay longer than a month.
So getting ~1% of the 2% that clicked through of the fraction of people who noticed the impression....might be better burning the cash to save on heating costs.
If WT has snazzier ads that get attention better, and a high click-through-rate because those ads close the deal, and they are more successful in converting trials into revenue, then it might be a positive ROI for WT to run ads.