Compared to various Xbox models, the PlayStation models were generally custom designed to a specific set of hardware and software criteria that aren't fully mirrored on Windows PC.
You're talking about the devices that can fully be turned into a PC. Sure, the hardware set is a specific thing (just like Xbox, though I guess they have two versions). However, the only thing that makes it not work like a PC is the software.
Yes, it is a non-zero cost. I'm pretty sure the dollar cost isn't the reason for it though. They care about the opportunity cost of not having exclusives. The PC ports made them profit. It just wasn't as much as they hoped, and it made the console less desirable.
You're talking about the devices that can fully be turned into a PC. Sure, the hardware set is a specific thing (just like Xbox, though I guess they have two versions). However, the only thing that makes it not work like a PC is the software.
Yes, it is a non-zero cost. I'm pretty sure the dollar cost isn't the reason for it though. They care about the opportunity cost of not having exclusives. The PC ports made them profit. It just wasn't as much as they hoped, and it made the console less desirable.
If PC game sales are cannibalizing PS sales, then there is a higher cost to creating and selling a PC port than just porting the game.