You have to understand the question: I don't mean we won't have any interest in the next PlayStation; I'm simply wondering why anyone should even mention the PS4 at this point in the current generation's lifespan.
First of all, Sony has never wavered in their 10-year-span stance for the PS3. Now, the 10 years could include the inclusion of a new PlayStation console along with the continuance of the PS3, as they point towards the PS2's long-running lifespan (currently 2000 – 2009). This means we could feasibly see the PS4 in 2012 or something (6 years after the PS3's launch). However, while I certainly understand that the industry is constantly in "forward-thinking" mode, which isn't necessarily a bad thing, I really can't see any PS4-related articles gaining a lot of interest. The gaming media is awfully good at jumping the gun, but we've already seen rumored spec pieces regarding the next PlayStation, and we have to admit…that's pushing it. First of all, there are plenty of gamers out there who haven't made the leap to the PS3 yet, and secondly, every sign points towards a long run for the PS3 with no evidence of a PS4 coming "sooner than expected."
The economy sucks right now, Sony wants to continue to establish the PS3, and the defining software has only just recently begun to arrive. One could argue that it began with MGS4 in June of last year, and we'll take more steps with the likes of Killzone 2 , God of War III , Gran Turismo 5 , Heavy Rain , etc. The PS3 has a loooong ways to go, and if you step back and examine the situation from afar, you'll see the system sitting – perhaps not in its infancy stage – but certainly in its youthful, burgeoning stage. The PSN is rising, Home is here and I think we all agree that is in the infancy stages, and we're still awaiting the price drop that puts the machine at the "sweet spot" (so said one analyst). The PS3 remains one of the most talked-about systems in history so maybe it's inevitable that the PS4 will garner plenty of early attention, but let's not get that far ahead of ourselves.
It's a dangerously slippery slope. Before long, we'll start writing news articles about what might happen in 2058, all the while ignoring the press releases sitting in our inboxes. Let's just take it easy, people.