LO
Before any contract was awarded on JSF - in 1996 - there was a plan to fund two engines all the way through the program. Because P&W already had the F119 in EMD, and the JSF engine was expected to build on F119, it was a leader-follower arrangement whereby P&W supported the X-plane program and the development aircraft, and GE/RR designed a new-centerline engine on a later schedule, but would be ready for full-rate production.
In the late 1980s early 1990s, the GE YF120 engine competed directly against the PW YF119 engine for what was then the ATF (Advanced Tactical Fighter) program which became the F-22 Raptor. Both engines were funded during the development stages. Pratt's engine won the competition in the end. This was only after P&W made it known to Congress and the Pentagon that if they lost this competition they would shutter (close down) their military engine operation outside of West Palm Beach, Florida and manage what was left of their military engine business from East Hartford, Connecticut. At that time there really wasn't much left of their military engine business, only what they were able to competitively win internationally on the F-16, F-15 and as sole source on the USAF C-17 program. The GE /Rolls Royce F136 engine built on the technology gained from the YF120 engine plus what Rolls Royce brought to the table.
IMHO, what has happened to create the single source engine scenario for the F-35 was the cost overruns and subsequent cancellation of the F-22 Raptor program after only 200 some aircraft being produced.
TD