Well yeah but Starcraft is still going on strong and it also came out by the end of 97, brood war in 98. The difference is the game is so fukn good , no need for that many mods, we got trigger maps for that. You just got to enter Battle.net and you'll see theres over 200,000 + people playin at any 1 time.
Also, a little offtopic, theres this other game that seems interesting too, not that it can be compared to Supreme Commander on the epic scale of battles, but still epic on its own right

The game is Spore, and you can start playin from the begining of Evoulution, you read right, from the bacteria micro world, to space faring civilization. Can do a little bit of everything, a little sims with your cratures, a little simcity with creating your civilization's cities, little bit of Civilization style gameplay with dyplomacy with neighbors, conquering through economic, cultural or of course military machines. Little bit of 2001:Space oddeysey. Has everything. I found on yahoo some movies from the GDC of last year where Will Wright, the author of the sims, simcity, and now spre, talks about the game. The movie is 1 hour long , but the site has some other movie clips from E3 at the right of the screen. here you go:
http://video.google.com/videoplay?docid=-262774490184348066&q=Will+Wright
If you dont want to hear the introduction, fast forward to 12 minutes and he'll be talking bout spore then...
I hope we can have space battles on that game, but till' now I havent heard anything related to massive space battles, so ill keep looking for that.
Enjoy
Monc34