I'm going to chime in here as a Best Buy employee, well technically Geek Squad, but whatever. Way at the bottom of the totem pole, nothing remotely official, but hopefully able to add some insight.
1: We didn't know they were killing it either. I literally learned about it from this thread, yay communication.
2: I'm almost 98% sure I know why it's dead: Total Tech Support. It's a new program we started selling last week, but I think this week is when we start actually advertising it. For $200 a year you get free, well almost everything. Geek Squad support for all your computers? Check. Car stereo installations for free? Check. Massively discounted in-home services? Check. Discounts on replacement plans, all sorts of shit. Honestly it's pretty crazy how much the company is giving you for free with this plan.
Here's the thing, they've already stated they plan on losing fuckloads of money because of it. It's a massive loss leader. Basically anything done by Geek Squad is now free if you have it. Having appliances set up is damn near free. Work on your car is either free, or hugely discounted. All of those profits are simply gone, in the hopes people will buy more shit. Geek Squad is basically a pure profit machine, and they are giving that up to hopefully sell more products.
GCU probably never made the company any money, in my experience most people with GCU never actually bought much of anything else. Now with Total Tech Support, they have an even bigger loss leader. They likely realized that having 2 loss leaders like that was a really bad idea, especially if GCU isn't really making them anything. People with GCU don't seem to buy much else, they just want games. People with TTS can buy literally anything in the store and the plan benefits them in some way. There is a lot more long-term profit potential if the plan works (and in the test markets, it has worked very well), meaning that they have no need for using games as a loss leader any longer.
3: the way they've gone about it is complete shit. Not telling existing customers is shitty as Hell. Not even bothering to tell employees, so they find out when suddenly the register won't ring it up, is simply fucking retarded. But I do get why GCU is dead.
I worked at BB for 4 years, when they first started gamer's club (with the @Gamer magazine) and when they switched to GCU (started $120->$60). I've been through various rebranding/changes for services and protection plans... while the TTS sounds like a nice plan, based on experience, the actual launching product will suck and will be fine tuned overtime (i.e. not worth the asking price at launch). Also based on experience with BB, one thing has nothing to do with the other, what does a protection/service plan have anything to do with discounted videogames???