It's all PR speak. Why advertise next year's model when you are still trying to sell this year's? As soon as you confirm a PS5 in any official capacity, you hemorrhage potential sales of the PS4, as there will always be people apt to wait instead of buying the current console.
The problem with industry leaks is exactly what we're seeing right now. We all love us some rumors and reports but they come with a heavy price sometimes for companies that aren't ready to either confirm or deny anything. As a result, people take every single statement and remark out of context and over analyze it. I do believe that there will be something along the lines of a "PS4K" considering the amount of sources claiming that the rumors are true, but I don't know whether the successor to PS4 will be a PS5 or not. And that's probably what Yoshida is referring to. For all we know, the PS4K or whatever the heck it's called could be what we're calling the PS5 here.
I think it's all about the name, too. Will there be a fifth PlayStation console? Well, of course! Will it be called the "PlayStation 5"? Maybe, maybe not.
If they start talking about PS5 already, they're going to remove all the (already minimal) interest in PS4K. They're not that stupid. They'll play dumb and give us the "no plans" routine until they're good and ready to move into a new generation.
Yeah, Sony has kind of put themselves in a tricky situation with these PS4.5 rumors, and the fact that they haven't issued a response has only made matters worse.
Questions about the PS5 will always be inevitable, but it feels as though these reports of a mid-generation hardware upgrade have forced Sony's hand way earlier than schedule. Maybe plans are in place for Sony to shake up its console production plan, iterating on hardware every three to four years. If that is the case, the console audience will need a re-education at an event such as E3, particularly now that the PS4.5 have caused a bit of a kerfuffle.
There will be a PS5 at some point, though if rumors of the PS4 Neo are true, it could definitely delay the need for a PS5 for awhile.
Given how the PlayStation brand is Sony's bread and butter these days, I think a PS5 is an inevitability. That said, it can be under a different kind of name so in effect, it won't be the "PS5," but rather, something keeping up with it in spirit.
And I echo the replies of the staff. This PS4K, NEO, or whatever Sony wants to call it is kind of a step-up to a PS4.5, which could mean a ton of things. Does this mean Sony will release upgraded consoles every few years from now on? Will this just be a revision like the PS3 Slim that's blown out of proportion? Is this Sony's way of slowly integrating PC-like incremental upgrades to its PlayStation platform? Your guess is as good as mine at this point.
Logically, a PS5 is a no-brainer given how strong the PS4 is selling so far, and how entrenched the PlayStation brand is with gamers. But who knows, though? Sometimes companies make the damnest things, but I hope this isn't one of those instances.