Sony is blocking crossplay, why?

We already know MS is open to cross-play with other consoles and Sony is blocking it, probably because they're in the lead, they want more people to buy PS4s because that's what a majority of the market owns so people that want to game with friends online need to get a PS4. They lose that advantage if people can just buy the Xbox One X and still play Blops IIII with their friends on PS4, and considering Sony needs gaming division revenues to keep the rest of the company afloat, doesn't surprise me they won't agree.

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