I wouldnt rely on this.

VG247 reckons it cannot be patched in:

https://www.vg247.com/2016/09/08/ps4-pro-doesnt-support-4k-blu-ray-because-streaming-is-the-future-and-it-cant-be-patch-in/

No games is much bigger BS.

Gamesradar are illiterate half-wits who can't even comprehend the article they are basing their own piece on.
The Guardian piece itself actually states:

Gamesradar's take: "Although House told The Guardian that he didn't think it would be necessary, it would theoretically be possible to patch in support for 4K Blu-ray down the line." is simply a failure of reading comprehension.  NOW, I would hope that they ARE using a decent enough drive which could be firmware flashed to enable BD4K discs, but if we are basing things off of the Guardian article AS Gamesradar claims it is, that is simply not true and is directly denied by Sony. 

Charging for PSN online play and then raising the price is bigger BS.

This lack of UHD disc support is amusing, but a simple solution is to simply not buy the upgrade.

It sucks for those who have collected many 4k Blu Ray disks. It definitely doesnt sound like the best choice for a 4k TV. For gaming its great. I had no plans on buying a Xbox Slim but now im considering buying one due to the player.

HOW is that a BS??? Was the Xbox 360 not supporting Blue Ray the biggest BS microsoft made last gen?? ........

sony have already smashed the Gen 8 win and are not playing catch up, why do they need a uhd player in a system that will go onto sell another 30-40m units and take the generation win regardless

a later model can have it included if it so needed

The Answer is obviously NO . For a gaming console the disc player is only relevant if it compromise or not the size of the Games which is not the case anymore since ps4 and X1 have launched. So 4KBD is  irrelevant as a feature when it comes to determine if a console product is good or not. I don't think 0.1% of poeple playing at 4k on pc with 4k monitor and tvs want a 4kBDplayer,why? Because they SIMPLY DON'T CARE!

- They probably would have to increase the selling price by 50 or 100 with a 4k player. 

- There is nothing wrong with PS4, being a PS4, a gaming console only. 

- The world of movies is moving onto streaming, this is why Netflix is so big. And have you not noticed? They were pushing Netflix. 

- The jury's out on Mark Cerny. He could be credited with ps4's current success. 

Microsoft set the standard there and their fans showed Sony they'd put stupid not to follow.  

Even their price increase.  Their only matching the xbox rates.  

Sony were actually the ones who started giving games away free for ps plus.  Something which was good for the consumer and Microsoft followed.  

Sony did paid online the right way and I'm ever grateful for it.  so many good free games over the years on ps3/vita/ps4.