Chobel
Member
Everyone is always quick to jump onto blaming Microsoft for this, because of the context in which this comes up all the time.
The actual answer here is that PSN and Xbox Live standards are directly incompatible with each other. That is, if you want cross-platform play, you effectively have to pick either Xbox Live or PSN, and then they can also play with PC (since there's no effective standard there, unless you're working through Steam - or you go with Xbox Live, which is supported in the OS as of Windows 10).
This comes up and people blame Microsoft specifically because it's something that was implemented between PC and PSN first. I can guarantee that the same thing would be happening if a PS4 version of a game launched after the X1 and PC versions already are out and have cross-platform multiplayer.
The user-facing quality standards are a big thing for Microsoft and Xbox Live, which is another reason why it's difficult for developers to add in support for that post-release for the purposes of making it cross-platform. When games implement this sort of thing from the start, it actually works quite well - for example, in Shadowrun (PC balance issues aside), Skulls of the Shogun, and Fusion: Sentient/Genesis (though those were a different type of cross-platform interaction).
Yes, Microsoft is in part to blame, because of the way their service is set up, and because of the standards and requirements that they have. However, to completely absolve other platform holders from blame in this topic is intellectually dishonest, at the very least.
Oh please, it's only MS. Dragon Quest X had Cross-platform between PC, Wii U and 3DS. The PS4 (which come later next year) will support cross-play.