I'm suffering from this syndrome not so much from Valve, but other game publishers. At least Valve actually delivers games on a fairly steady basis, *and* continues content for TF2/Left 4 Dead 1/2. And Valve also brings us many pleasant surprises just about out of thin air that have been great games (read: TF2, Portal, Left 4 Dead).
If anything, Blizzard and Bioware are the two biggest "Valve Time" abusers right now.
The worst offender here by far is Bioware/EA's The Old Republic. Where the hell is Star Wars: The Old Republic? I have an Origin pre-order for that game and I have yet to see a peep about a beta in my in box, and its already September (read: 2 months to "holiday season" window they talk about). A beta, which I signed up for in 2009. And wasn't TOR supposed to be out by May this year? The fact that they refuse to put an offical release date on the game worries me that we won't see that until at least 2012, if not 2013.
Honorable mention for "Valve Time" goes to Blizzard. Where's Blizzard's new great MMO? Starcraft 2: Zerg/Protoss? Diablo 3? Project Titan? I somehow doubt Blizzard can walk-the-talk on that four Blizzard Titles being out by 2014, unless those titles are WOW expansions. Or two WOW expansions, a count down clock site, and either Diablo 3 or the next Starcraft Expansion.
EDIT: The best way to go through life is to not give a shit about a video game release until you see the disks in your hands, or a Steam Download you can play that day. Beyond the context of this rant post, I stopped caring about TOR months ago. I suppose that right there would count as "Valve Time Fatigue", except not for Valve.