I think the existing structures of US FF programs mean that Delta introducing MQD (Medallion Qualifying Dollars) is unlikely to apply to Qantas.

Using the examples of SYD-PER (2,445 miles) and JFK-LAX (2,475 miles):

DL (and the other US programs) base their status qualification based on miles flown.
- JFK-LAX return for the first week in February prices out at USD $322 return for the cheapest fare
- Ignore any bonuses, you would need to fly 10 return trips to achieve about 50,000 miles and hence qualify for Gold Medallion on Delta (the equivalent of QF Gold), for a cost of $3,220.
- The only way to earn more under the current DL structure would be to fly on an M economy fare (or above), which nets you 150% of miles flown (same if you actually bought a business class ticket). M fares are pricing out at $1,375, so you would have to do 7 round trips (4,950 miles plus 50% bonus) to reach 50,000 miles, or $9,625.

Because QF bases their status eligibility on status credits (which to a greater degree factor in the fare class of the ticket than the US programs):
- A return SYD-PER earns you 50 SC, you need to do 14 return flights, for a cost of $534 each or $7,476 in total to reach Gold on QF
- If you choose a Flexi Saver fare (which would net you 100 SC for the return trip, cost goes up to $858, times 7 return trips is $6,006
- If you flew business, $3,131 round-trip for 200 SC, you'd need to do 3.5 trips, or $10.958.50.

Of course, there are ways to game the QF system (you could fly 14 JFK-LAX return trips on AA for the same price as Delta or $4,508 to net you 700 SC) but the average QFF will be spending more to reach status.

"Mileage running" to achieve status is not as cost efficient on QFF as it is in the US programs, which is what I think DL changes are meant to get around. DL's lowest fares will still earn 100% mileage credit towards status under the new system, but you can't just fly 10 cheap fares to earn the mileage flown requirement without also meeting the spend requirement.