Some seemingly offhanded remarks recently, by Shu Yoshida, got people asking if there would be a PS5 at all, in the wake of a PS4 upgrade.
There won't be, and I'll explain why.
Apple... iStore. Google... Google Play.
Sony doesn't have this. They don't have their own ecosystem -- instead they push the reset button each and every time they release a new console architecture. The PS4 changes all that.
Take a good look at the PS4 design -- it's the first in Sony's long console history that effectively correlates with a standard PC-style architecture. This is intentional -- they want it to be upgradable, so they can create a software ecosystem, like Android and iOS have, which can allow for hardware upgrades to play, and purchase, older software, on a per-device basis. Your old PS4 run outta gas? No sweat, PS4k is here now! Buy one, you're happy because you can transfer all your games, and some of the newer games will offer improved performance, features, and resolution on titles you probably already own.
Sony's R&D costs? Chopped considerably. Each console is nothing more than an upgrade over the old. Nothing fancy or new every seven years. And guess what? You got a mobile device with 8 x64 cores (side note: they are NOT using x86 instructions on PS4 games! They need to address 8GB of RAM!), 6-8 GB of memory (less is needed with lower res textures), and a decent GPU (GPU power could be lower, you usually just need to tune display and texture resolution, unless the game is vertex bandwidth constrained or somesuch)? No sweat, download that digital game and go!
Sony wants to be your gaming SERVICE, not merely your potential console maker every seven years. They want you INVESTED in your Sony account. They NEVER want you to switch to XBox, Apple, Google, Steam, GOG, Origin, or any other system.
On top of that, there's an even bigger reason there will never be a PS5. If you're not into hardware tech, you may not realize that current semiconductor technology is reaching its limits, and there are no affordable (i.e. reasonable) solutions which even take us much past about 2020. Hardware fabrication will stop at about 7 nm transistor gate size, and 7 nm chips will be SUPER expensive (i.e. not console-worthy). We'll be lucky to see affordable 10 nm chips (the next fab scale past the current scale of 14 nm most high-end fabrication facilities operate at in 2016) by 2020 -- they already exist, but affordable? Nope. The machines that make them cost about $1 BILLION USD *each*! Make a factory with 8-12 of those? About half the chips they made are failures? Guess how much a company has to charge to make those chips not lose money, given that the current 14 nm upgrade cost about $500M per machine, and the fab companies need to recover that, too!
7 nm will simply be beyond the typical consumer until, probably, about 2025-2030. Now think about the console life cycle -- the first consoles are spendy (remember the PS4 started at 28nm), and then they lower their price by making the consoles cheaper to make. This has traditionally come from an increase in chip production efficiency, via increasing the number of chips that can fit on a wafer (which are produced by those expensive fab machines). Sony has very likely reduced the cost of the PS4 by making the processor 1/4th the scale it was in 2013 -- allowing 4 times as many to be produced in the same amount of time (remember the fab company charges more though, because the machines that make the 14 nm chips cost a lot more than the 28 nm machines did).
Sony is smart -- they realize that, if they make a new console, it has to be considerably more powerful than the PS4, AND it has to be no more expensive than the PS4 was in 2013. If they make the chip about twice as big (see PS4k), and it costs twice as much per unit wafer area as 28 nm did, they can make a $400 console that is an upgrade from the PS4, and yet not lose tons of money in the process. If they make one four times as big, and charge $500-$600 for it, they will get tons of bad press, and lose marketshare (see: PS3 release). If they make an entire console that has that chip, 32 GB of memory, a 1 TB SSD, USB 3.1 ports, etc. etc. then they need to charge a good $1000, and they get laughed out of the market.
But wait! Can't they just do that in 4 years time, when the price of said console drops to $500-$600? Nope. Because to do that, it'd probably have to be at the 10 nm scale (SSDs and memory just won't drop all that much), and then the console is, basically, stuck at that price point for AT LEAST A DECADE, while 7 nm tech becomes affordable. Will that work? No way.
There will not be a PS5 in the foreseeable future. There will certainly be a PS4k. There will likely be a PS4k Turbo mk II, Actual 4K edition (lets face it, a doubled GPU won't do 4K for games. 1440p yeah, but not 4K), but there will probably not be a PS5, ever.
This is the "last console generation" -- that doesn't mean there won't be better consoles. Merely that they will largely resemble the current ones, unlike the past.