Great minds think alike :P I also suggested a Netflix deal in the very first post I initially made about the potential for a UHD upgrade and why Sony might potentially just have to keep quiet until the contract is up (it was one of the first Ps4Pro threads we had after revea) I also mentioned that I wanted to make a thread predicting UHD will come via firmware, and now everyone's discussing this as a possibility. I have planted the seeds of doubt lol. Or it's just coincidence and no one noticed, idk 

I see no reason for Sony to willfully negate to include an UHD player at all. The cost is insignificant considering the is a standard blu ray drive in it already and they went to the added expense of adding an additional USB port in the rear and keeping the light bar/strip and optical port(whilst absent in the Slim possibly due to space limitations). Sony were all over DVD for the PS2 and all over Blu Ray for the PS3 and it's not like they cheaped out on the OG PS4 with expensive capacitive buttons(later revised to physical) a light bar and Sony themed screws for the internal hard drive tray.

I guess we will see. I'm very interested to know if it is possible or not because I've read articles from years back that stated there were these crazy 4 layer prototype discs being tested and how you didn't need anything necessary to read the extra layers except a driver update. What was really a lot more surprising for me is that they can patch in HDR. TBone was right, and he basically just proved 90% of GAF wrong. It's fucking great 

MS doesnt show how much money the xbox division makes or loses. the act itself is kind of telling, but its just pure assumption, we have no actual or confirmed data. 

Perhaps, but there's not much in it. The drive is a $15.50 premium over the drive in the old model (source below). I guess Sony have to live in the here and now, but blu-ray drives used to be wildly more expensive than they are now, I expect it won't make too much difference to profit per console to Microsoft before long.

http://www.businesswire.com/news/home/20160805005103/en/IHS-Markit-Teardown-Analysis-Microsoft%E2%80%99s-Xbox-Brings

I believe this is a case of Sony trying to push 4k streaming (as part of a deal with the likes of Netflix). The grumbles of "patching UHD in later" may be false unofficial damage control or Sony knows they can have their cake and eat it too.

Why? over 80% of the 4k televisions have 4k streaming build in to the television, more power effecient, easier with the TV remote, streaming services are not something you need a console for anymore.

The HDR update is surreal... Were they hiding it all these years or was it a recent discovery? I did read that there were 100GB blu ray disks being tested years ago, even bigger than 100GB.

It depends on what drive is in the PS4 Pro and what it is capable of. Alot of drives cover multiple blu ray mediums....

Will have to wait for a proper Pro/Slim tear down and inspection of the blu ray drive. Does the Slim have HDMI 2.0??

The reading speed exceeds to 128mb ps, while normal blu rays only go to 58mb p/s. Ultra hd blu rays can be triple layered instead of dual. So unless the PS4 P has a drive that supports these bandwith and supports bdxl which is very unlikely, the PS4 won't support UHD blu ray just as every other blu ray player out there. If you want to play UHD discs you either buy an Xone the Samsung ultra hd blu ray player or the panasonic. Building a UHD drive in your pc is also possible I guess.

So has this thread proved one way or the other with actual evidence of Ms/Sony's OEM bulk costs for both the xbox slim and ps4 pro/slim?

We need the total cost of all components and total costs of making both systems complete to determine how much either company is making or losing when it comes to just the 4k drive as I assume they're not exact in costs without the drive.

I figured you'd update the OP with found evidence since you targeted a member of the forum specifically in it.