It won't matter just like the ps4pro upscaling won't matter.

Why?

Because at the end of the day both will produce the best looking visuals for their respective time frames when it comes to consoles and that's what people will care about.

Not sure who that is or why his opinion is any more of an opinion than mine.

I'm basing mine on actual experience, as i've gamed at 4K for several years on Pc: I've ran games in 4K with a single GTX 780 3Gb, 780 SLI, and now a 980Ti. My experience tells me you can most certainly game natively at 4K, comfortably at great image quality, with a GPU and bandwidth closer to the latter and 12Gb of memory. Its not even a question...lol 

Common sense says RotTR, Gears Ultimate and Forza Apex on PC all ran 4K with that target performance, and they were not nearly as optimized as in a console envrironment leveraging all cores/threads. In fact, their multithreaded optimization left a lot to be desired on PC. 

It is with this experience i'm sure that they plan on targetting first party games at 4K on Scorpio.

Strange that you don't know him since he answered to you on several threads were you made such simple calculations to say Scorpio will be fully capable of doing full 4k... You even ignored the post in here that a GPU with 9Tflops had to use dynamic resolution on Gears to keep 30-45fps. But sure Scorpio 6 will certainly be enough to make all games 4k ultra 6fps.

That is  with what is most likely a much faster CPU and more RAM(the Scorpio is rumored to have either 8 or 12 GB RAM) in the PC running Gears 4 at 4K. I don't know much about PC gear but I'm assuming a good CPU and more RAM assist the GPU in providing good visuals.

And steady framerate... Scorpio is pretty much more powerfull than PS4Pro but nowhere near enought for full 4K on ultra at a decent framerate... if MS pushed only for that it would be pretty much a waste for most users (who don't have 4k TV) instead of allowing for better IQ on 1080p.

It seems anything the X1 can currently do at 900p or 1080p, the X1 can handle at 4K. I'm sure we'll see scaling for 60 fps experiences like Halo 5 and perhaps 6.

Hopefully the Scorpio also adds 4GB of additional RAM so we can have better textures as well.

Bottom line, Scorpio will be able to deliver native 4K experiences when PS4 Pro can't. Just like PS4 could deliver 1080p experiences more often.

According to Digital Foundry, GoW Ultimate does 4K/30-60 fps with a GTX 980 Ti. With settings higher than the console version is likely running.

That video card seems to be about $400-$500. The same card seems to run any X1/PS4 game at 4K/30-60 fps with higher graphics settings.

EDIT: Furthermore, the GTX 1070 is also capable of 4K/30 in many 8th gen for around $400-$500. With ease if settings are at par with consoles. It won't cost $900 to get Gow4 running at 4K.

You guys have to keep in mind that you are comparing PC specs to console specs, they've never really linked up as in what you will end up getting.
Always going to be the one I say, but if you look at GTA5 running on the 2005 hardware inside the X360 and try to put together a PC with similar specs (512mb of ram total) it wouldn't even boot the games starting logos, never mind actually attempt to run.

Forza Horizon 3 was pretty interesting.

I can run it 4K Ultra 30 FPS locked with 8xMSAA with my 980Ti. At 60fps setting with  Ultra + 4xMSAA framerate drops into the 40's. I can basically run it High Details at 60 fps, or a High & Ultra Mix with 2xMSAA with less severe drops into the lower 50's.

It will be interesting to see what design choices they take with Scorpio in this series, but the IQ at 4K Ultra with 8xMSAA is absolutely stunning.

IMO for console, this level of detail will be hella appreciated even if 30 fps lock is required.