Assumptions are necessary when we don't have perfect information. I'm making the (IMO) fairly safe assumption that most of the PC's on the Steam survey that are more powerful than the PS4 are actually being used for games (insofar as they could be considered part of a valid target market for a multiplatform developer). You don't have to agree with that assumption if you don't want to but if you're arguing it's unlikely then you're assuming too.
I'm a) not arguing, and b) not assuming anything. I am genuinely curious about the number of PC gamers with console-comparable hardware and the number with better hardware because it would resolve a number of endless circle-jerk discussions on the forums. And really, that's my only interest.
On the topic of your Mac, it's fair to assume that Macs are being used less for gaming than PC's given equal specs. So the easy enough solution would be to exclude Macs and Linux in any counts you make (which is possible in the survey).
That's another dangerous assumption. I'd ignore the Mac statistics entirely given Steam indicates 1 out of 4 Mac owners has an AMD processor, so there's clearly a lot of Hackintosh machines out there. There is obviously a OS X (and linux) market for games otherwise Valve wouldn't have bothered at all, but that's about all you can say unless Steam start published actual numbers.
Also, you're making the argument that not all PC's of >console gaming potential are necessarily being used for gaming but I'm not sure what ultimate argument you're trying to make by stating that? Should we not be considering those PC's part of the gaming market? If so, then would you agree the same constraint should be applied to the console market? Afterall not everyone who buys a console regularly games on it. Sure they will at first but after a year or so that console may start collecting dust. You've given your example of having a powerful gaming Mac that doesn't get used for games but I can match that with my own example of the XB360 I bought last generation which saw great use for the first 6-12 months, then collected dust for a couple of years before RROD'ing on me. I'm not saying either of us represent a majority or really prove any kind of point, but what applies to one can certainly apply to the other.
Again, I'm not arguing anything, I'm seeking the facts. I'm partisan in this, I'm a gamer and by this I mean I'm not a console gamer or a PC gamer, I game on anything and everything. I'm not trying prove that consoles or PC have more active gamers or vice versa.
But taking your points one by one, yes the same considerations should apply to both markets as far as that makes sense. For example, PCs are by nature multi-purpose and while consoles are certainly more varied in there capabilities, their is little risk in assuming somebody bought an Xbox One to run Photoshop to run photoshop. Photoshop is a reason to own a decent GPU on PC and not game, or game little. Last gen people bought PS3s as a cheap Blu-ray player and at one point it was the top device for using Netflix. We've moved on a generation and it's far less likely anybody has bought a new console for Blu-ray or to watch Netflix since pretty much anything can be used to access Netflix so gaming would seem to be the primary reason to now a current console sales demonstrated pretty early in the generation. WATCH_DOGS, which came out about six months after launch, sold more copies on PS4/XBO than PS3/360.
You mention your 360 and how little you use it. I guess this depends why you bought it? I get the sense you're a primarily a PC gamer and if your bought the 360 to play platform exclusive games then that would explain the lack of use, unless you just want to explain why. If the former, you're the almost the revere of me. I use Macs for work, play and the occasional gaming experience that consoles can't provide, Starcraft 2, LoL, WoW and I prefer to Minecraft on PC as well because of the mods.
On your final point, either one of us could be representative of a fair share of the market. It's entirely an unknown. There are simply too many unknowns which is really my motivation to ask quests and query rationale. I don't exist on a side (console/PC) here, I don't really understand people who do mentally and emotionally anchor themselves to product or a brand.
