ORAC,
Honestly, and with respect, i really do think you might be lining events up and seeing patterns that aren't there.
The JPO were, by around 2008/9, ready to can the second engine. The full costs of the redesign in 2004/5 were coming in, as were the real software development costs, and Congress had already tried to get the second engine canned. On the political side, both P&W and GE had well organised and very effective teams lobbying Congress. Steady production of F135 engines wasn't, as far as I saw, a factor in canning the F136. it was a pure budget drill, and in the end driven more by the DoD and the politicians than by P&W.
I don't know the details behind the reliability graphs, and I honestly can't explain the large 'spike' improvement in 2012, or the subsequent drop. I'd be interested to see what the graphs looked like before 2012 - I know that these figures were being closely watched by the JPO as well as the rest of the DoD.
Like I said, I won't even try to sugar coat these reports - the figures are poor and will need to be improved. That said, I've seen at least two, possibly three, UK aircraft programmes that showed similar trends.
Best regards as ever to those tendin' the engine'
Engines