Very few pc people buy games on PC, that's why developers like to delay the release of it if they even make one.
Piracy is definitely a major problem on PC. Developers of games like The Witcher 2 have came out and said that their games were pirated 5 times more than they were purchased on PC. I can see why that would make a publisher hesitate to support PC gaming but there are still millions of people who buy games on PC. Steam is massive and many people, including myself have gigantic Steam libraries of games we have purchased. I just checked and I own 474 games on Steam and that isn't counting the ones I own on Battle.net, Origin, GOG, Windows 10 Store, and uPlay. PC gaming is my main platform and I personally have never pirated a game in my life.
I also took a look at the Steam Spy listing for GTA V, Rockstar's previous game. 5,449,108 people own GTA V on Steam and it is still in the top 10 sellers list on Steam almost every month. Keep in mind that this game doesn't even redeem through Steam if you buy it anywhere else because Rockstar has their own code redemption and game launcher service. Anyone who bought a physical copy of the game or bought it from digital retailers besides Steam like Amazon, Humble Store, and Green Man Gaming isn't even included in that 5.5 million Steam player count.
So yes, piracy is a major problem for PC gaming but that doesn't mean it isn't worth it to put your game out on that platform. There are still millions (hundreds of millions in GTA's case) of dollars to be made. I highly doubt that Rockstar is going to give up hundreds of millions of dollars in PC sales just because Red Dead 2 will end up getting pirated at some point.
There is also a newish, very hard to break DRM called Denuvo that has kept pirates from getting their hands on popular games like Arkham Knight and Rise of the Tomb Raider for 7-8 months after release on PC. They are still getting in eventually but most game sales occur in the months before these games are cracked anyways. I would much rather see publishers invest in better DRM like Denuvo to combat the piracy problem than delay the PC release. Delaying it probably isn't going to make PC pirates go out and buy a console and the game.
