Why don't Butterfly Labs etc just use the ASICs themselves to mine for profit while the difficulty is low.
Sensible answers only, no painfully naive answers based on childish Libertarian principles please.
Because their profit margin on selling ASICs is going to be higher than their profit margin mining (just as those who sold equipment to miners in the gold rush days made more money than the miners).
While we don't know exactly how much money BFL has spent on development, we do know that no matter how much power they throw at the network there's a hard limit on how many BTC they could mine each day. The most they could mine per day is 3600 BTC and that's only in theory because they'd have to control the network to mine each day's total output. Their electricity obviously wouldn't be free so they'd need to recover both their ASIC development costs plus their overheads from the sale of mined BTC. Bear in mind that difficulty will not remain low for very long once BFL's ASIC power is thrown at the network, whether it's by themselves or by their customers.
Whatever problems ASIC customers are going to have would also apply to any ASIC vendor using their own product for mining - to just tread water and maintain the shame share of the network, they're going to have to invest in more equipment as time goes on and basically spend increasing amounts of money to maintain the same return.
