JD - I suspect that the starting point was the UK decision to dump the F-35B, probably because of a lack of confidence that it would ever enter service, due to a combination of technical, economic and doctrinal factors in the US.
This removed JFH's role as a "bridge" to the F-35B, which had been very important. Removing one FJ fleet was seen as a major cost savings. Typhoon was unthinkable. GR4 had done CAS, and other things like Raptor and Storm Shadow depended on it completely, and consequently...