Perhaps - just as a single type works just fine for OS and AD?
Although the FTA is supposed to meet all strategic and tactical AT requirements and FSTA is supposed to meet our future AAR needs (and some limited AT), the truth is that no matter how good our STSA is, it is only a Short Term solution. But the need for C-17 scale capability has been proved - so it'd be a brave person who assumed that this need could be taken over entirely by A400M.
Tranche 2 of the 130 replacement and most of FTA could be met by A400M which could also offer a very useful AAR role. Having bought 130J, it makes obvious sense to try to make it work as it was supposed to all along. If you include FSTA, then that still makes 4 types..........which is fewer than at present!