The PS4 Pro does not include a 4K UHD player because Sony believes that the market is moving away from physical media.
That's according to SIE boss Andrew House, who told The Guardian that 4K streaming was a more important feature.
Our feeling is that while physical media continues to be a big part of the games business, we see a trend on video towards streaming,” he said. Certainly with our user base, it's the second biggest use case for people's time on the system so we place more emphasis on that area.”
House also added that it will not be possible to add 4K UHD to PS4 Pro via a firmware update, either.
At last night's PlayStation Meeting Sony highlighted its ongoing relationship with Netflix, specifically mentioning its support for the service's 4K content – which will include the second series of Narcos and the new Luke Cage show.
House said during the presentation that 6,000 hours' worth of 4K content will be available on Netflix for PS4 Pro this year. It's not yet known whether other 4K streaming services, such as Amazon Prime Video, will also be supported.
Sony launched its own 4K streaming service earlier this year.