I haven't been to a LAN party in about 10 years. It's really easy to get the same experience nowadays with broadband and a microphone.
Then no offense, but your friends suck. There's still no way sitting at home alone in your basement playing with friends online and yelling at them over teamspeak compares to packing 12-15 friends into same basement and duking it out all night long. Sure, you can trash talk over the mic, but there's still going to be times you just need to grab something soft and wail it at your friend when he curbstomps you... Or the joys of building a massive tower of dew from everyones empties.. or waiting to see who crashes first and then raiding his hard drive for that uber pr0n collection he's been hiding....
Don't get me wrong, broadband has changed the world, but there are some things that just aren't the same even with broadband. Hell, my wife's computer is upstairs in her own little room, and I always feel bad that's she's getting left out of the fun when the party's at our place (I keep trying to convince her to move her gear downstairs for the even, but no love).. it's a world of difference being in the same room together versus even being on separate floors, let alone zip codes. (yes, a wife that enjoys lan parties... granted she's more apt to enjoy the simple classics, ala Q3 and Unreal then "complicated" ones in her opinion, like TF2.. but it's a start).
Overall, I think this is a mistake on Blizzard's part. There *are* those of us who still do actual physical lan parties, and in some instances, network dependency in a game can be a BITCH... case in point, new fangled games that have *one* way to patch, direct from the internet. You have 15 people sharing a broadband connection, you know how long it takes for each of them to download a separate 1-2 gig patch? And if it's an EA game, good lord, forget it, I think they're using C64s as their patch servers.... Before all this "lets assume everyone is connected to the internet all the time" mentality, one person could grab the latest patches (from home, before the lan party), bring them to the party, share out the EXEs, and everyone could patch direct from that... now, especially with Steam games, it's always a crapshoot to see who all is upgraded to the latest and how many people will need to download (at the same time) slowing everyone to a crawl. Even trying to plan ahead you can still get burned (last lan party I think it was, there was a TF2 update that came out the night before before the lanparty.. some people had patched the previous weekend, but nooooo, we still had to sit through the mess)