I think you're right Luke it's as much about stifling the B team approach from the big boys as it is about cost control. Does start to dilute the principle of cutting edge though.
One of the commentators on Sky TV said "If spec gear boxes had been in place before Barnard's famous semi auto and flappy paddle gearboxes appeared, where would gearbox tech be now?"
I agree with the sentiment, but given that the current design is pretty locked down, any innovation is iterative, not creative. They're all going to be 8 steel gear, semi automatic transmissions, no matter who builds it.
I'd prefer the regulations be opened up so that there CAN be some creativity. Otherwise, if building a gearbox (on top of chassis, aerodynamics, suspension etc.) is keeping privateers out of the sport, maybe a 'low cost' option should be available. Maybe sprinkle things around: if you supply engines, you cannot supply transmissions. Would be a good way for Williams to raise a little extra cash.