Yes schraube, but you're forgetting something here. That count you just made doesn't mention Medal of Honor, which is based on Quake3, nor does it mention Return to Castle Wolfenstein, which is based on Quake3, nor does it mention Urban Terror, which is based on Quake3. But your Half-Life number includes Counter-Strike, which is the bulk of it & all the other mods under the banner of Half-Life.
Also, Doom2 featured 4 man DM & it rocked. I remember playing it every single night. And back then, you paid by the minute to play it. I used to spend $50 a month playing that game & I loved it. We held LAN parties based on Doom2, where we'd have 4 games going on at once, this back in the day of Coax Cable networking.
Plainly Half-life 2 is going to be a great game, but that doesn't mean that it will have the same "Feel" as Half-Life 1, which is why it is so popular with people. It Feels right. Urban Terror feels like you are running through a foot & a half of water. I don't care if Half-Life 2 is graphically beautiful, it needs to be playable in all the right ways to be as good as Half-Life 1.
At any rate, don't discount 4 man DM. If it is done right, it is very fun.