From the article it sounds like she was used to hearing his voice when he was talking to his radio chums.
To me that sounds like he didn't usually contact her personally.
Though It's starting to sound though like foul play , maybe someone shot down his drone and maybe accidentally or by design shot him and then Carol.
And then burnt the tent , after a fight where the table got knocked over.
I've gone between them getting lost which doesn't make sense if he was expererenced, to them starting a new life together to now thinking it's possible that they were murdered. Maybe by someone annoyed by the drone, either by the noise or the fear it would discover something they wanted and needed kept hidden. Maybe drone footage captured them doing something illegal.
I agree, it sounds like she was used to hearing his voice when he was talking to his radio chums and most probably didn't contact her personally. The fact that she was so quick to dismiss him as dead and is packing up his belongings tells me that their relationship (even after 50 years) wasn't all that good. Sounds to me like they were married but more for convenience after all the years they were together. Too much hassle at their age to start again.
I'm not too sure about the shooting down of the drone and then Carol and Russell being shot down. Firearms in Australia are quite restricted for one thing, and for another, I would have thought the police would have found some evidence of spent cartridges, especially given they used dogs. However, saying that, it's not unusual for illegal cannabis growing activities in the bush, though I would be surprised if someone would have had an illegal crop so close to where people frequently camped.
I wonder who bought the drone? Unfortunately, police information is at best, limited and sketchy (as always).
I do believe personally though that there is something very amiss and that they didn't go "walkabout" and mysteriously disappear.