Crysis 2 had NO demo. It had a beta multiplayer that closed down after a little bit. Assuming people want to try before they buy (a perfectly acceptable practice), the only way they can is by pirating it. I know alot of people who pirated it just to see if they liked it, and then bought it from Steam (when it was on steam :/).
Another is to see if it will run on your rig. We all have experienced a game not running great on our rigs at max, or any setting. Its a horrible feeling. Alot of players downloaded the pirated version just to test it, and then bought it. It really makes complete sense C2 is the most pirated game. Its the most graphic intense, thus people want to test before they buy. NO DEMO available lead to this, and its alot more common for games to not have a demo. I really dont understand it.
Yes there are people out there who just want to save money too. Another notion to get out of the way is that is most common on the PC. Thats just a lie. Pirating takes place on consoles just as much, if not more. Mod chips, modded game downloads, its all out there, with tons of seeds too. Its not all on the PC. It happens EVERYWHERE.
Leaving Steam was Cryteks biggest mistake. They missed the crazy holiday sales, a big opportunity to get more sales. I know I bought almost 20 games discounted on Steam this year with the black friday ones included. Its an integral part of PC gaming, and ignoring it is like ignoring people giving you money, it makes no sense.
Like Gabe Newell said, you have to offer a service customers value to keep them coming and paying. Steam does this, League of Legends does this, WOW does this, Battlelog kind of does this, all very VERY successful in the realm of PC gaming. PC gaming is FAR from dead, in fact, its getting bigger than its EVER been! Companies need to stop blaming pirates and look to their decisions they made with their game.
Crysis 2, very limited PC options in the beginning, turned alot of people off to it, hard to mod in the beginning, tons of problems online getting games started, lag, bad server browser, ditching Crysis 1 style, and copy and pasting COD into it, etc. Even now, you cant connect to a server and download a custom map, it has to be done externally, a feature that even Quake 3 had Crysis 2 lacks. Word got around on what a bad "port" Crysis 2 was on the PC. Having a smooth launch is so critical to avoid the bad-mouthing and future sales of your game.
Sorry Crytek I love you guys, I love your games, but please dont focus on the wrong things when trying to figure out what went wrong. Look at the most popular titles on PC and how amazingly successful they are (League of Legends, WOW, BF3, CS:S, Starcraft 2, etc), and what you guys did.
There is a quote I love, its something like "A man cannot master more than one thing at a time". Focus is key. Splitting development for all three platforms was the key mistake, but the others I mentioned above certainly had their impact as well.
Links:
Crysis 2 most pirated:
http://www.tomshardware.com/news/Crysis-battlefield-gears-of-war-call-of-duty,14406.html
Steams huge success in 2011:
http://www.tomshardware.com/news/Steam-Valve-Skyrim-Modern-Warfare-3-Deus-Ex,14444.html