The euthanasia of the FET engine (F-136) was driven by many on 'the Hill' (lobbyists?) and Pentagon but not the Program Office. In fact, at the time the whole second engine debate was going on, the incumbent Program Executive Officer was vehemently against removing it. He cited reliability examples of the early F-16 engine, faults and issues with the AV-8 sole engine provider etc as clear reasons to maintain a parallel development option to mitigate the discovery of 'issues' in development and the potential grounding of an entire fleet of 'air vehicles' when fielded. The FET worked for 15 years to develop F-136 and was 80% complete when it was axed; in many respects it had advantages over the P&W F-135 engine. Taking the law of (un)intended consequences to one side for a moment, the decision to remove the F-136 will, ultimately, prove to be the wrong one imho. Pratt & Witney now have 12+ customers (governments) over a barrel. Without the F-136 there is nothing to meaningfully hold P&W's feet to the fire over cost, schedule or performance.
To quote HASC Chairman Buck McKeon: “I had hoped that the GE / Rolls-Royce competitive engine could be a model for government-industry partnership to drive down the cost of important weapons systems. As our military faces a dramatic decline in their budgets in the near term, this is just the beginning of the wave of cost-cutting decisions that both the military and industry will have to make”.