I am not at all saying that the PS4 sales are a fluke or that it is still selling well because of the hardcore. I am not saying there is any sort of "mass market" that is suddenly going to go out and buy the One. What I am saying is, the hardcore tends to be the early adopters for any new technology, and early on the PS4 sold a shitton (I am almost sure they were at over 3:1 in March or April.) I think at some point something is going to cause more people to upgrade their 360's. Period. Believe it or not, there are people who only buy consoles for Halo, or Sports games.
Based on trends, the people who upgrade their 360 will go PS4. IIRC Sony said that something like 40% of the current PS4 owners are 360 --> PS4 gamers. That's a pretty large amount and it shows that PS4 is selling beyond the userbase that bought PS3.
There's really no data that suggests current 360 gamers are just waiting in the wings ready to buy an Xbox One as soon as .... reasons. It's this same logic that Nintendo applied to the Wii --> Wii U transition and look what happened. Before anyone says stuff like "but Wii is different because casual audience". Well ... the biggest sellers on the Xbox brand these past few years has been "casual" stuff like EA Sports games, CoD, Kinect games, and Minecraft.
My biggest point is, at some point the gap is going to become closer and the One is GOING to start selling. Look at the last gen and the difference early on between the PS3/360 and the numbers at the end of the generation. Things just have a way of working themselves out somehow.
I don't know if you intended to pull a "but PS3 caught up..." argument but that comparison has been thoroughly debunked numerous times. Closing the gap means that Xbox One not only sells better than it currently is (which will probably happen ... maybe) but it means that the PS4 either slows down considerably (why would the market leader slow down while 2nd place increases in sales?) or the XBox One starts selling so much more than the PS4 that it is able to reduce or close the gap. I simply do not see that happening in NPD, let alone the world.
Again, I am not at all saying that the PS4 is not the superior console or that it is only selling to the hardcore. I just feel that there is in fact an "untapped" market (as you put it) which is going to upgrade their console at some point. I have recently come to see that the PS4 being so much more of a gaming/powerful console is probably not the only reason it has been selling so well to this point.
Edit:
THIS is the thought that I am trying to convey as well.
There is definitely an untapped market and I 100% agree with that observation. Thing is, according to historical trends, the "untapped market" tends to go with the market leader, lending even more sales to the market leader, making the market leader even more of a market leader.
And the thing is: this often happens regardless of previous-gen winners or previous loyalty. SEGA Genesis stole huge swaths of the NES market with the "cool guy" advertisement and being the go-to console for sports games and arcade ports. PS1 stole the market from both SEGA and Nintendo. Then Nintendo stole the market from both Microsoft and Sony with the Wii while Sony and Microsoft fought over the carcass of the PS2 installed base. And now PS4 appears to simply be mopping up the remnants of a game industry that is (in my opinion) going through a market contraction in the console segment with little to no competition from Microsoft and Nintendo.
I have ranted far too often in this thread. It's about the Xbox One price cut. I think the price cut will make waves for 1-3 months and then it'll go back to normal once the "pre-season" in 2015 begins and Microsoft stops supporting the box for a while. Will it close the gap worldwide? No. Will it close the gap in NPD? Probably not. Will it win the months of November and December? Eh, maybe.