[Look the Statix III is a 65nm chip. Alterra isn't even making it anymore. They want to sell Stratix IV and soon they will need to sell Stratix V. They want that inventory gone. Gone from their website, gone from wholesalers, gone from retail outlets. when Stratix V is in full production it becomes the high end part and the Statix IV becomes the value segment. The Stratix III is just a third wheel.
I'm not sure it works that way, though - there's always customers out there who've built designs around older chips and for whatever reason either can't or don't want to move over to the latest and greatest. From what I've seen the FPGA vendors are really slow at taking older chips out of production for this exact reason.
Case in point: The CEO (and probably sole proprietor) of ZTEX did.
Before the 1.15x module, with its 8 Amp core voltage supply, came the 1.15d module, and the originally recommended supply for it
http://www.ztex.de/usb-fpga-1/pwr-1.0.e.html only sported a 3 Amp core voltage supply!
He found out the hard way that all these unrolled loops of SHA-2 cause something like 50% of all flip-flops on the FPGA to switch simultaneously, and
thus blowing even the most conservative power estimations out of the water.
That board wasn't really designed for Bitcoin mining in the first place - he's been selling them on eBay for ages as generic FPGA development boards.