Warcraft 3 isn't limited to online play, so it's late 2004, not 2002.
By "every one since 2002", I meant the last one to not require an internet connection came out in 2002, and everything since then did - thus, "every one since 2002".
There were a few problems with your stataments, I corrected your statement for you.
It's tough to tell, but you seem to be trying to make two points - first, that a number somewhere south of the number of WoW subscriptions alone represents the entire online gamer market, and that pretty much the entire remainder of the world's population must therefore represent the single-player PC gamer market, and second, that Blizzard is not allowed to design a multiplayer game and then say "you should play our game in multiplayer." I would contest both, to be honest. To be fair, I would contest the latter less - the other Diablo games had single player modes that worked just fine. But this isn't really about single vs. multiplayer, it's about online vs. offline. And I can understand the people who say "I won't play it because I can't be online," that's fair, though they are very few in number. What I really don't get are the people who say "I won't play it because I couldn't play it if I weren't online" despite probably having always-on broadband for the last decade (there may be no such people participating in this particular discussion, but one gets the impression there are many of them elsewhere). And if Blizzard imagines the single-player mode of Diablo 3 to be less like D1/D2 and more like solo questing in WoW, where the online features are still an integral part of the game, more power to them.
That sort of leads to something else, too. There's no doubt that part of Blizzard's motivation here is copy protection. But unlike Sony or Ubisoft or whoever is crippling drivers and making their legitimate wares unusable today, Blizzard is approaching the problem with pretty much all carrot, no stick. I figure, if a company is going to actively defend their right to get paid for their works, that's the way to do it.
Tangent: people tend to pirate media for two reasons - price and convenience. It's hard to beat free, but the latter's a big point too. Aside from torrent downloads being fast and convenient, often DRM hiccups on games give people problems and drive them to pirate the game just to play something they paid for legitimately. And when they do finally get the game going, nothing is lost. Diablo 3, on the other hand, will have tangible features that many people will use, and that the pirate servers simply will not be able to offer (particularly cross-game friends list and cash auction house), in addition to probably requiring either special configuration or locally-run server emulation software. The non-pirate experience will be, on average, demonstrably better, instead of worse. And then... I did say it's hard to beat free, but it's not impossible. I fully expect that anyone budget-conscious should have no problem at least recouping the purchase price of the game through the cash auction house. The moment you hit positive expected value on your investment in the game just through selling stuff you picked up during normal gameplay, you
have beat free. Pirate servers will be fragmented, so I doubt any sort of strong cash-based item market will spring up around them. In short, I think Diablo 3 will actually compete strongly on both points that typically swing in favor of piracy, and that it may not be all that widely pirated at all.