The question is not whether Mac would be an adequate platform for some games. Nobody wants an adequate gaming device. People want something that is clearly better than any alternative in the kind of gaming they are interested in.
Consoles are a cost-effective way of playing games on a big screen. PCs can offer both extreme performance and extreme backward compatibility. Mobile games can be played anywhere. Switch is a cheap device that combines the convenience of mobile gaming with a dedicated controller. What would be the niche where expensive Macs clearly beat the competition?
I am very late to this thread, but I finally have some space.
So let me first agree with you a bit - there is pretty much no (gaming) niche where expensive Macs beat their (gaming) competition.
Where I mainly disagree is "Nobody wants an adequate gaming device." I’d contend that a lot of people are perfectly happy with an adequate gaming device, if the content is there. Hell, they are more than OK with that even for a
dedicated gaming device, or the Switch wouldn’t outsell everything in the console market. And Macs aren’t dedicated gaming devices, gaming is just one of their potential uses.
So, IF the games were available for the Macs, they should do as well as on any other non-gaming focussed device such as, say, iPads. Better, arguably, since Mac buyers can’t be the most cash strapped clientele. The question is whether developing iOS/MacOS or Windows/MacOS titles offer sufficient ROI to justify supporting MacOS and their AS graphics architecture.
Just as with any entertainment content, that is bound to vary from title to title, and there are beancounters who will make guesses and put those into spreadsheets, and present the results at board meetings. A problem for MacOS gaming is the uncertainty of those guesses - how many AS Macs will be sold? To what demographic? What will their interest be in title X? The cost side of things is much easier to predict.
I’m quite convinced that for instance Baldurs Gate 3 will pay for itself nicely. As would Diablo 4, or Civilization X. Would Nier:Automata, GTA X, xSouls y, et cetera? Well that would require a lot more risk taking.
I think the baseline gaming capabilities that Apple has established for their AS Macs is quite robust, very roughly on par with the PS4, and thus adequate for just about any current and most upcoming content. However, the big game publishers are not known for taking risks, so for the next couple of years I wouldn’t be surprised to see more titles originating from iOS focused developers/publishers than from the traditional console/PC side.