Industry insider Ahsan Rasheed, nicknamed Thuway, is known as a fairly reliable source of rumors that has been proven wrong rarely. Today he gave an interesting snippet of information about Final Fantasy XV, that apparently, according to his sources, used to be a PS4 exclusive (and not just a PS3 exclusive in the guise of Final Fantasy Versus XIII)

FFXV PS4 Exclusivity, even to this day, some insiders claim, was a thing; and these insiders are about as trustworthy as they come.

Thuway went on to theorize that the reason behind the multiplatform nature of the revealed title might be that Sony didn't care to pay for exclusivity, even if this seems to be just his personal speculation:

It could also be because Sony didn't want to open their checkbook. Honestly, exclusivity in this day and age is stupid.

Of course, as with all the information coming from insiders like Rasheed, we should consider this a rumor. Unfortunately it's unlikely that we'll ever hear something more solid about it anytime soon, as this kind of deals are not spoken about in public outside of post-mortem interviews that normally happen several years afterwards.

If it's true, I tend to agree with Thuway. There are better ways to spend resources than purchasing third party exclusives, especially on the long run funding first party IPs tend to be a better idea.