The first thing i would like to point out is that the common rationale that hardware was a big issue in hindering the sales seems to bring up the rebuttal: "when did gamers get so pissed at developers for trying to push the envelope and make a game that was truly cutting edge visually?" or something similar.
I don't think that anyone is really pissed about it ( except maybe some bolo with a integrated graphics card that went out and paid for the game ) other than crytek. I'm sure most people had the same reaction I did: "That game looks sweet, too bad my system can't run it" and then they don't buy the game, and then crytek only sells 1 million copies.
another huge difference between crysis and console games was advertising. ok, crysis only sold around a million copies, and halo 3 had surpassed 8 million several months ago, who knows what its at now. but for months all you could fraggin see anywhere you looked was master chief. they even made a new mountain dew flavor for the game release. idiots were walking around dressed in the halo armor. not to mention that it was the third in a series. the only reason i even heard of crysis is because i have the g4 channel, and the jokes going around saying that it wasn't really a game, it was just a hardware benchmark. It would have been easy to do more to promote the game in the mainstream, like microsoft/bungie did with halo, but it just didn't happen. they could have even worked out a deal with invidia and/or intel. buy this redonkulous video card/processor and get crysis free. or buy crysis and get $40 off a geforce 10800 or intel octo core extreme 5ghz and that would give people who bought the game and were able to play it on minimum setting an incentive to upgrade the video card, as well as being a factor in deciding whether or not to buy the game at all. The least they could have done was release it on steam. i almost won't buy a game unless i can get it from steam.
speaking of which, like Mumblez said, just take a look at valve's survey summary.
http://www.steampowered.com/status/survey.html
as of 15 july only 38% of the gamers surveed had 2 GB or more of ram, and only around 9% of gamers had vista with dx10. and this is a survey of people who already buy pc games for their computer.
I had a geforce 7600 and p4 3.0ghz when the game came out. it was like watching a powerpoint slideshow of a fps, even with everything turned to low. i upgraded to a 7800 gtx and core 2 duo 2.0 ghz, and it was playable with most settings on low and a couple on medium (in vista 32 bit).
I actually enjoyed playing crysis, despite all the bad reviews and how crappy it looked. it was not "truly open ended game play" as it was touted, it was just another shooter game. it actually kind of reminded me of timeshift. It wan't the best game in the world, but it was enjoyable.
for crysis, like other games i play, the single player mode is almost an afterthought. multiplayer is where its at. multiplayer is also the solution to piracy. pc gamers want to frag other people, not spend the whole single player mode with stealth on sniping people with an assault rifle. and maybe the crysis multiplayer is good, but i can't play it without getting pwned due to slow frame rates. it at least looks interesting.
I burn through games like crazy, i will play it for a couple days, and get sick of it, and usually never play it again unless it has that special something. the last one that did was counterstrike:source, and before that was quake III arena. cod4 looks promising, but i haven't played it on pc yet, just ps3 and 360.
/rant