It has been speculated that Final Fantasy XV could have been a PS4 exclusive.
This makes sense since Final Fantasy Versus XIII was going to be a PS3 exclusive. Industry insider Ahsan Rasheed tweeted that Final Fantasy XV was a PS4 exclusive and many other industry insiders knew about this.
Rasheed assumed the only reason Final Fantasy XV became multiplatform is because Sony didn’t care to pay the amount of money for exclusivity. That is why the game will be released for the Xbox One too sometime in the future.