Surely, the way ahead is for a drone tanker to fuel a drone fighter ?
No, the optimum is for a large multipoint tanker, to reach an orbit point at a safe range behind the combat zone and fill up a load of drone tankers such as the MQ-25 which can then tour the CAPs filling up the fighters or join COMAOs penetrating enemy airspace.
That frees up the larger tankers to get back on the ground ASAP to refuel and get back up again maximising their TOT. As well as reducing their risk, as HVAs, of being engaged.