I'm hearing that, once Points Club is removed, the ability to earn status credits on Classic Rewards will be unlocked through one of Qantas' credit card partners.
Also, I'm expecting that Qantas will give at least 12 months of notice before increasing the "retain status" thresholds to match the "attain" thresholds. This means that, if you're currently trying to renew status for this membership year, you can expect that you'll only need the lower "retain" amount of status credits. The new, higher retain thresholds are likely to come into effect in late 2027, with an exact date to be announced later this year.