Chances are both Xbox One & PS4 had to wait for the same reason & they are both getting it now because they worked out the problem that was holding it back.
Good point, I don't think the average reader here knows what coming. Everyone and I mean everyone has to comply with the same HTML5 <video> standards which now includes smooth streaming (adaptive streaming), DRM (both Playready for VOD and WMDRM10 for DTCP-IP) and Metadata. It's very possible Sony, besides using Microsoft's DRM is also using or complying with Microsoft's player APIs. I.E. They have to wait for updates from Microsoft so Sony supporting Blu-ray 3D at about the same time Microsoft supports it is exactly as you state.
The HTML 5 adaptive streaming player is used by every feature in both consoles (both will be supporting the same features). The HTML5 <video> player will support 3D as will the blu-ray player and Skype.
Both consoles will likely be serving blu-ray to other platforms in the home and that requires adaptive streaming which will use the HTML5 <video> adaptive streaming player in clients on the home network.
This is not speculation! It's part of what HTML 5.0 will support and it's known as RUI or DLNA CVP2.
Head mounted VR goggles will also be used with HTML5 <video> 3D....
All this is timed to start in 2014 (Certification for DLNA CVP2 platforms starts Septemner 2014); FCC mandate for cable companies requiring them to support DLNA CVP2, HTML 5.0 which has the APIs to Java and DLNA to support DLNA CVP2 and ATSC 2.0 OTA which uses the blu-ray codec and supports 1080P & S3D, XTV and Non Realtime Transmission.