It's only opening for Australian citizens and permanent residents (and other exempts). These flights are likely to still be mostly empty. Don't know where you are looking from, but I'm seeing K bucket open on many dates in early November and $1282 one-way K fares from LAX. These K fares have a seasonal black-out from Nov 12th to Nov 22nd. They are still being stingy with opening K or lower from late November through the end of January, but then you start seeing more dates with K bucket open.

Previously, they typically only had Y/B or Y/B/M bucket open further out all the way through the end-of-schedule. Looking on ExpertFlyer, I see wide-open V bucket availability on flights for July 2nd and onwards. I suspect this is currently the date when DL's feels comfortable more broadly accepting reservations from tourists. The cheapest fares will require a roundtrip purchase. The cheapest fares on LAX-SYD are currently $1705 roundtrip ($774.30 each way base) BE X fares with a 7-day minimum stay requirement. These have seasonal restrictions, so you don't see availability on them until July 24th as they are blacked out for earlier in July. There are also one-way BE V fares for not too much more at $875 ($822.30 base).