I actually never believed that the business is sustainable in the first place. How many people are computer enthusiasts that will want to shell out a significant premium for the absolute fastest chip they can get? The premium for top grade chip is very steep, and generally are of interest only to extreme overclockers, which makes sense for competition. In our day to day usage, that extra 100 to 200 Mhz that we can squeeze out of it is not going to make a material impact to my user experience. In addition, to squeeze out that extra Mhz, you need to maintain some cutting edge cooling solution that can keep up with the heat and power consumption.
In addition, CPU refresh cycle is quite fast. So after testing and having a bunch of CPUs, it may be hard to sell them off as it gets near to the next cycle. So I do wonder if they managed to sell off all their CPUs in the end without making a loss on any of them to begin with.