Why doesn't Butterfly Labs use their ASIC machines for their own mining process? Butterfly Labs produces ASIC hardware for bitcoin mining. I guess it is cheap for them to produce a 1500 Ghash/sec machine. They could have many of them for a very reduced price. Why, instead of selling them, do not they use them for their own mining so they get more money?
They are choosing a less risky option.  By selling now, they get the price of the machine no matter what happens to the BitCoin economy.   They are defining their core competency as being in the hardware business not the cryptocurrency business.

The same could be said for people selling pickaxes during the Gold Rush.  Why not use the pickaxes to mine gold?  They got the money for the pickaxes up front, then they were out of the picture.  They didn't have to choose a place to prospect and worry about how long the gold would last. They chose to be in the pickaxe business not the mining business.  Incidentally, during the Gold Rush it was these peripheral entrepreneurs that made much more than your typical gold miner.