But the RAF always seems so very keen to move the C-130 on, and I'm never really sure why - is cost of ownership really high?
IIRC the original intent, back in the early 90s, was to reduce the number of transport types.
We had the C-130, VC-10C and Belslow. The C-130 was seen as too small for the FRES and other planned loads and, with no “east of Suez”, the A-400 was seen as perfect to replace all in the AT role (Beagle can talk on the pax and AAR aspects.
Then 9/11 and Afghanistan happened and we ended up leading/buying C-17s just the A-400s started arriving, and we still needed the C-130s. Back to multiple types again
culling fleets saves money. We now see the need to keep the C-17, there is a political aspect for keeping the A-400 (with the belief all the problems are solvable and improvements achievable), which was already slated to go and would be politically embarrassing to now keep.
If the funds were available I am sure running on the J would be the preferred option, seeing as the training/logs etc are in place.
But buying another new type? Fantasy land.