Blu-ray was really struggling against HD DVD in a battle for what they thought was going to be a market as lucrative as DVD was at the time.
Therefore there was a huge incentive for Sony to "trojan" as many Blu-ray players into homes as possible. This ultimately led to them comfortably forcing HD DVD off the market (sales for HD DVD were far better than Blu-ray until the very minute the PS3 hit the US market when it was completely flipped the other way, and HD DVD never clawed it back after that)
This time around with UHD BD, it's a completely different thing. We have seen that BD even 10 years down the line, still hasn't overtaken DVD as the main video format. So although still a big market, nowhere near as lucrative as hoped. Partially due to streaming, but more due to the average person still finding DVD perfectly acceptable.
4K BDs will be a niche market, and will more likely share a similar sort of existence to that enjoyed by Laser Disc in the past. High end releases for the videophiles and big film enthusiasts. There is also no impotus to dethorn Blu-ray as the high definition option, as it is already their format.
So I don't really see why logically, Sony would want to just chuck in a UHD BD player for the sake of it? It was clear from multi DVD games that Blu-ray was offering a better capacity for the direction games were heading in too.
Microsoft on the otherhand know they have exhausted their best software arsenal, and don't have that much left to try and claw back marketshare from the PS4 globally. A UHD BD player could well be for some people, an upgrade that makes them change their purchase.
RIP Dad 25/11/51 - 13/12/13. You will be missed but never forgotten.
