Marketing is a major factor in gaming sales and devs that make great games don't want to have their awsome games be ported to an unpopular system like PC.
More likely they don't want to spend the time and money porting a console game to the PC given how low the sales will be. It's not just piracy, it's the fact that console-to-PC port games are aimed at a rather small minority of gamers who only own a PC. If you already own game X for your console, you're not going to buy it again for your PC, are you?
Cruel devs such as EA, are why some people stay away from PC gaming because companies like EA are known to care only about the money not what the player want and so the devs rush through because they want the MONEY so in the end the game quality sucks.
The fewer games EA makes for the PC, the better. Seriously, they're a terrible developer who ruin games made by other studios by buying them out and releasing sub-par sequels. If they give up on the PC market, there's a very good chance they'll stop buying up great PC developers and making shitty sequels of their games.
Bugs, the most annoying thing about PC games, if a person buys a game filled with bugs (for example a game like Space Empires V), so after he has a bug filled experience, he thinks that all PC games are filled with bugs.
Only an idiot would jump to the conclusion that if one game is full of bugs than all games on the same platform suffer from the same problem.
At last and not least copy protection, copy protection can be a very evil thing because if you play a game that requires the internet to finish installation and you don't have internet, than you just wasted 45$ for nothing
The number of PC gamers who do NOT have Internet access is, I imagine, so small that sales really aren't affected by the loss of revenue from them. I mean, I imagine there are more gamers with Internet access than there are gamers with DVD drives, yet nearly every single game released in the last 2 years has been on DVD.
Also, it ALWAYS states in the game's system requirements that you need an Internet connection to activate a game; if your computer doesn't meet the system requirements, you can hardly blame the developers for you wasting $45 because you didn't read the game's sys reqs.