That raises a completely different question though. Indeed, it very well may be the case that most people don't even know what crossplay is and just have no idea about anything about it and likely have no particular feelings due to that. Pretty hard to have any feelings if you have no clue what's going on or what something even is or anything. It very well may be just a vocal minority that cares in anyway, about this, at all.
...But in that case, why wouldn't Sony do it regardless? If it's just a vocal minority? Because that argument concedes that most people don't know about crossplay, and if they don't know about it, how would they, say, suddenly notice if it were to be enabled? They (Sony) surely have nothing at all to worry about in that case. Can't hurt sales or anything if most people don't even know what "crossplay" is to begin with. People would have to know about if for it to even have the chance of hurting anything. But if most people don't know, and very possibly will never know or care about this one way or the other, how could it possibly hurt them?
I know that's not what you're arguing here, but it's an interesting train of thought to me--any admission that most people don't even know what crossplay is would also be an admission that it would be pretty difficult to hurt sales or damage Sony in any meaningful way. At which point, you're just left with the benefits of consumers. Like I said, I know that's not the argument you're making. But it's very interesting to go down the road of how most people might not even be familiar with crossplay and whether it does or does not exist and what that all does or doesn't mean, and whether people would notice or not if it were to be enabled, etc, because going down that road just seems to completely destroy a lot of the arguments against Sony not letting it be turned on, but that's me.