Proposal: The amount of people on the forum who are very concerned that their PS4 will no longer be the most powerful PlayStation within six months and/or that the Xbox Scorpio will be more powerful than both their PS4 and the PS4K in 2017 suggests that hardware power is a really notable concern for many enthusiast gamers.
Yes, it's a concern for many enthusiast gamers, the hardcore that House mentioned. But like the ones who get high-end PCs, even if they are vocal in gaming forums or in the comments of gaming websites they are a minority of the market, as we can see in the Steam Spy numbers.
I think normal people will go to Best-Buy or similar and will be told: you have the PS4 and the high-end PS4, that is more expensive because adds 4K media support and runs the same games but slightly better visuals and performance. And they will decide without getting mad.
Most current PS4 users (casuals, mainstream) won't notice that a more powerful PS4 Neo existed (they may think it's a Slim or Elite version) or won't care about the extra horsepower.
I don't think so. At some point in the future, Neo will have its own successor, which it will be sold alongside to (it then becomes the cheap entry solution). At that point Sony is going to stop selling - and supporting - vanilla PS4.
Well, Neo would release around 3 years after the normal PS4. If you add another 3/4 years it would be time to go next gen and release a PS5 that may be compatible with PS4 games for full BC but would feature exclusive games that would take advantage of the extra horsepower.
I see Neo as a mid-gen update, like a Slim but on steroids. The next update would be a next gen console. I think it would be too complicated -specially for marketing- to have a 3 PS4 SKUs with different performance and features.