Certainly the firmware development time is costly, but it's also already been spent and other than ongoing maintenance, a cost that has most likely already been recouped as well.  The real question is are they continuing to put FPGA's in their new   "prosumer" oriented products, such as http://www.rme-audio.de/download/sheets/babyface_e.pdf (nb: the term "FPGA" is used 0 times in this document).

http://www.enterpoint.co.uk/moelbryn/raggedstone1.html indicates the starting point for just the spartan 3, and support chips is already above what most "prosumer" cards cost -- $100.00. Unlike custom VLSI, you can't just plop a FPGA on the pci bus. Note that the Xilinx isn't the only chip on this card: http://www.soundworks.dk/images/rme/hdsp9632_big.jpg -- there's at least 6 other chips in the "digital" part of the card, some of high-complexity/integration/cost based on their pincount -- in addition to the Xilinx chip. That includes an additional Xilinx chip (flash memory??) that is clearly visible on the above pictured board.

Some business people will give a back-of-the-envelope calculation that a $20.00 increase in parts cost translates to a $100.00 increase in consumer cost. And the above estimated $100 parts cost of an RME's fpga and support chips translates to a card that costs $500.00 more e.g. http://www.amazon.com/RME-Hammerfall-9652-Audio-Interface/dp/B0002H030S/

RME can and will continue to do what it does very well -- and priced at "you get what you pay for rates."

Just seems that since they've got the entire thing already programmed out in an FPGA, they could  build a VLSI at little incremental cost. It's not like they're starting from scratch... And given the look of the "BabyFace" perhaps some of their new products will indicate a shift towards this strategy (?).

Maybe I'm old fashioned, but I've always seen FPGA as something to use for one-off or very low-volume projects. For example

http://www.fpgaarcade.com/ :-) But I have no idea of how many cards RME sells a year. Actually, that would be a very interesting number, just to get an idea of the order-of-magnitude size of the "pro" end of the DAW market..

-- Niels