Although it didn't work out that way. Australia wanted to get away from having two fast jet platforms, with the purchase of the original 100 to replace the f-111 and fa-18ab. It's more cost effective to have one platform. UK is headed in that thinking too isn't it?
No, it was never planned that the F-35 would replace the Typhoon - too many eggs in one basket. It was presumed the F-35 would replace just
one GR4 sqn in 2020, alongside 5 Typhoon sons. However, with the slippages in the F35 it is possible that the early F1s might be extended and the later tranche 3 jets being used to provide the 6th squadron.
That would allow a cut in the F35 procurement to equip a single F-35B OCU/wing for maritime ops.