Your reading that PC basically has the MMO, RTS & some competitive shooters all to itself. While PC also gets all the main multi-platform games, its main exclusives would be the genres above like World of Warcraft, Company of Heroes, Civilization & Counter-Strike. Most other great games are indie titles, a lot are rough early access games but a few do release & are great games. Rest of steam, most of steam is full of junk titles that will run on a lot of devices, people buy & don't play.
+ All the good PC titles, in a lot of cases just wouldn't be ideal with a controller anyways - best those titles stay exclusive to PC. PC is ideal for them games for that reason, pretty much all other AAA games do better on console so you do see exclusives on consoles ranging from hack in slash, JRPGs and range of genres / games selling better.. Even the Vita was/is an ideal place for indie developers to create games for over other devices, depending on the game it can sell better depending on the device its released for.
PC, Consoles, Handholds, Mobile titles generally all have its own sort of games. Comes down to preference, GTA5 is a massive title & would of sold a lot more on PC if it released alongside the PS3/360 versions or even the PS4/XB1. Timed exclusives normally don't sell as well as they would if it was released within a short time period.