If by first evolving console you mean ps5, then yes. The next evolution and, higher powered PlayStation, will be the ps5.

Or, we could make claims that many systems before were evolving. The nes, with the mmc chips in carts, or the snes, with the superfx chips, or the Genesis with the 32x,.... yeah, the ps4 will certainly be the first.

I think this points more to the possibility of this gen having a shortened cycle. It will continue to sell, just like previous gens. but to offer a 4k PS4 is bad juju. I know most will defend this, but for most avg. consumers and casual gamers it is only going to confuse them. Look at the Wii/WiiU and 3ds/NEW 3ds. most do not read up on this, and will be irritated by so many variations. It also defeats the reason most people buy a console, standardization.

This is going to split the PS4 userbase into 4 sections
1. Standard PS4
2. "NEW" PS4
3. PS4 w/ standard PS VR
4. "NEW" PS4 w/ PS VR

Better to bring in PS5 with integrated PSVR earlier, than do this.

Maybe it'll be the first console to successfully evolve. Sega CD didn't go particularly far, and 32x was dead on arrival.

You mean consoles with additions.
That has happened for over 30 years, since at least Colecovision.

No, I am talking about a console that gets improved make overs throughout its lifecycle. 

I am talking about Sony releasing what would be the equivalent of an iPhone 6S. A second generation PS4 that becomes the new standard vonaole at retale, retaining complete compatability with all PS4 software, apps, and services, but runs everything fast, better, and smother.

This would not ever have any exclusive titlws or gimics that are not available to day one PS4 owners. I is simply a product that new comers would get a product that is up to date, anf the core market can upgrade to after five years for the best experience.

The only reason this makes since is because a PS5 before the mid 2020 will mot offer a significant enough increase in power usher in a new generation of play. So jumping to a PS5 will only split the userbase, and create distrust due to the lack of any reasonable need to upgrade. Instead an improved PS4 woyld offer a more polished version of current gen gaming, while not forcing people to upgrade for the next micro atep just to play the latest Uncharted or Gran Turismo.

I think creating an incrementaly better PS4 will hurt Sony more than releasing the PS5 sooner. 

If they did that, I would just wait out on their next console to hit it's half life before I buy it, since I know that a better looking, AND PERFORMING version will come out a few years later. 

It's one thing to have a revised looking system, which is smaller, and more energy effecient, As opposed to a newer system that is smaller, energy effecient, and has improved performance in terms of ram, GPU, CPU bumps. 

Most early adopters accept the fact that they are going to be purchasing the system when it is the most expensive, but then to offer a new version,  years later that is also a better spec'd machine, and cheaper. Yeah, this is a bigger deal, than just a larger hard drive.

So, like the PS2 Slimline? GBC? DS Lite? Or the top-loader NES? All those Mastersystem versions? All of which had improved form factors and hardware, but play the same software as the original, just better.

I don't think that will happen. The reason why consoles have made it thus far is to give every user the same experience. But having an additional processing box for PlayStation VR make perfect sense...

That said, I do think the console life cycle will defiantly be shorter and maybe that's the only reason. Just expect shorter console generations...

Isn't the New 3DS an improved version of the 3DS with improved processor speed that actually gives a visible bump to existing games?

No