To expand on the point above from amir0x, the reason for the messaging change at Sony after looking at their sparse lineup for the first 6-9 months is clear: Without casual audiences to fill the coffers at publishers, AAA games can't get made like they used to.
Despite what some people might say, PS4 wasn't being billed as a haven for games with a casual appeal and modest graphics; it was lining itself up to try to be a core gamer's boner-inducing dream come true right from the outset. It's Sony's go-to strategy, with mixed results. It doesn't really know how to sell a console by virtue of games alone, only potential for how much BIGGER and SHINIER and AWESOMER they could be, until reality sets in again. See for reference of when it goes bad: the first half of the PS3, Vita.
Xbox One puts itself in a similar position, with a huge elephant in the room from their PR disaster at E3 2013, to boot.
And Wii U, despite how I love it, isn't what it might have been. And publishers, to a certain extent, were probably banking on it a little as a console to make cheaper games for higher returns with no one thinking differently about it.
NO ONE in the console market is filling the void left by Wii, and the money that was once spent at retail on the much-derided "wagglefests", while possibly trickling back into the industry through other platforms like iOS, is not the relatively-consistent monetary returns they had during the peak years of the Wii. And without that, we're going to see a spike in risk aversion and fewer games. Just like we saw in the opening act of the PS4 life cycle.
Sony sees the void left by the Wii's special place in the console ecosystem and knows it will limp along on a comparatively sparse library of titles unless it can generate sales to the wider audience, and fast. But when you sell games on being bigger and better, efforts that seem scaled back by comparison will never garner the same attention, always getting drowned out.
Hence the message change.
