which MEANS negotiating AU domains sales is still the better way of selling AU domains for the time being...
I don't agree with that.
If say "enduser X" is an auction and they want to win they might have a proxy of $10,000. They might think the auction will end at $1000 but they might have a proxy 10 times that just in case.
In a private sale scenario they might think the name is worth $1000. Likely they'll offer below that, eg $500. If the seller says "buy I want 10k" they'll probably just say "it isn't worth that" and walk away or just wait.
The dynamics are totally different, a private sale is about getting the name as cheaply as possible whereas an auction is about getting it at your limit or under. The private sale is the buyer against the seller, the auction is the buyer A against buyer B.
Personally I have negotiated with people in the past, they've said their limit is X, I've said I want 2X and they've said clearly no. I've then sent it to auction and they've bidded to 3X and lost the auction. Has happened a couple of times with me in the last few years. An auction dynamic is totally different to a private sale, there is no right or wrong way to sell in my view.