Maybe it cost them less than a "few" million to develop.
Even if it cost them $0 to develop the asic, the problem remains. Unless you would expect them to give it away for free.
That's not even taking in to account that ASICs will be profitable miners for a LONG time. If they could get it down to say, 25w for 1 GH/s, then difficulty would have to increase 49 times what it is now, with NO increase in price, for them to start being unprofitable in many areas. Granted, the payback period would be far extended if difficulty were to increase that much, but 49 times is 588 TH/s. Even if BFL only had a fraction of those sales, they would still payback far more than their initial investment.
Forget about electricity costs, Im not even factoring that in. That makes the problem for miners worse, not better. I used some numbers to illustrate my point, but the underlying cause remains true regardless of the actual numbers, as long as you assume a trivial marginal cost compared to market value, which is a fair assumption for a bitcoin asic.
The real problem is that BFL or any early asic provider will price their product at a level the market will currently bear. You can argue what that is, but I would say 6-12 months before you earn back your investment seems like a sensible investment, they will sell at that price. But that 12 months ROI, will become 12 years and 120 years as more and more asics flood the market at ever lower prices. How can you know how long it will take before it gets there? As a miner, you cant. You could write a check for 1TH asic miner expecting it to break even in 6 months but never actually get there.
The only way I can see this going wrong for BFL
Oh, but Im not worried about BFL. If they are indeed first to market, Im sure they will make a nice pile of money, and they should, they deserve it. Its the miners that will get in to trouble.