Yeah I don't get it either although I doubt they have a 20 GH/s chip. More like 10? to 20? chips per "rig". So 25 units might be 500 chips. Still it doesn't seem to make any sense. 25 units @ $30K ea = $750K. 100 units @ $12K ea = $1.2 mil? Since incremental cost is small why would they want to limit themselves to 25 units and thus have to price them so high as to be inferior to other offerings?
If I were in a position where I thought I'd be able to have a head start on manufacturing ASICs that blew all other miners out of the water, I'd be highly motivated to just keep it all to myself as I pretty much dominated mining.
Maybe that is exactly what they are doing. I would assume an ASIC manufacturer would want to proliferate their chips to as wide an audience as possible, any other goal seems counterproductive to maximizing their profit. If they were looking to mine themselves, they would want the opposite. Just enough sales to pay the NRE costs, while still keeping the competition low to maximize mining profits.
Official explanation...
We only have enough chips in our first run to build 25 units. We don't want to run more than this off the presses until we know that there's enough demand for these ASICs. Once the first batch is out, it will be relatively easy and quick to produce more. Yes, future prices will probably be lower, given Moore's law.
How much would it cost to produce 25 more units? Or 100?