I doubt that Blizzard games previous to WoW had any kind of outrageous numbers of player (by that I mean I'm sure they were fairly standard PC gamer numbers).
Do you recognize the names "Warcraft," "Starcraft", and "Diablo"? The only Epic title that even approaches their worldwide success is Gears. Heck, it's not much of an exaggeration to credit Starcraft with jump-starting the entire South Korean economy, and it went on to become the best-selling PC game ever (until being dethroned by The Sims a few years ago). Gears of War's lifetime sales have only just caught up with Warcraft III's
pre-orders from back in 2002 (and that was a PC-only title).
Despite your sureness, those are not "fairly standard PC gamer numbers". Every one of Blizzard's games since the original Warcraft: Orcs and Humans has been a market-defining smash success.
What Mike said makes sense, it's hard to see how Blizzard has been so successful over the years when they so willingly work on a game for three years and then just throw it in the trashcan. Anyone that has been following them for a while knows that they have done it more than once or twice.
Do you think shipping those games would've translated to even greater success for Blizzard? In any case, as someone who has apparently "been following them for a while", why do you believe that Blizzard gained no value from those projects?
It's very important to note that 10 million subscribers or 2 million Battle.net registrations does not translate to those same numbers in players online as they would have you believe.
Warcraft 3, released in 2002, still posts over 250,000 unique players per week, and frequently far higher. No UT title has achieved more than a tiny fraction of that player activity, even within the first few months after launch. In fact, I'm conservatively understating those numbers because, frankly, I'm too lazy to pore through Battlenet's stats to substantiate the actual numbers, which appear to be astonishingly higher. Let's just close with the point that Warcraft 3's
smallest server hosts more officially-sanctioned tournament players per week than the entire communities for UT99, UT2k4, and UT3 put together - and that doesn't count any non-tournament play, which dwarfs the official tournaments.