Guys, the piece of the "Cheap Engine" puzzle that you keep missing is that this independently-developed "customer" engine wouldn't be locked into the same restrictive and expensive specs as the current 1.6L Turbo Hybrids instead it would be a cheaper, simpler 2.2L V6 Twin Turbo (like those used in IndyCar) likely with a "cheap ERS system" slapped onto it.
Paraphrased from http://www.bbc.com/sport/0/formula1/34629481
Crashews's comments