Right, but if they sell too much ASIC mining hardware, they will cut into their own mining revenue. That alone is enough for them to keep the price of blades high.
Actually it is the complete opposite. Why would ASICminer brother with the logistic (setup, pay for power/space/maintenance) to mine themselves if they can receive instant 1-2 years worth of bitcoin mining profit from people who can't do or don't care about math? In another words, why would anybody in their right mind turn down collecting 1-2 years worth of salary in advance today? Especially when you tells them in 1-2 years you will either be out of a job or your salary will be 1% of what you will be earning today for doing the same task (The current generation of ASIC useful life ends when difficulty increase 100 times in 1-2 years)?
There is a logical answer to all of this.
1. ASICMINER's farm acts as security for the network, it quite literally insures their hardware sales business by being as big or bigger than any other threat.
2. In much the same way, as AM increases the size of their farm, they increase demand on their hardware sales due to rising difficulty. A dangling carrot.
3. The farm provides predictable revenue, something hardware sales may not always provide.
