The impact of the pandemic era rollovers, credit card bonuses, etc have been well covered (I do think people are underplaying the impact of earning status on award travel). I do think people are ignoring a few things that are leading to higher elite levels relative to Delta's current thresholds

1) Increase in premium leisure travel (people spending more of their money on travel, hybrid work increasing three day weekends, baby boomers retiring on inflated home values, 401Ks, etc)
2) Impact of inflation - the $25K MQD threshold isn't that much anymore for many professionals in the era of $100 a person dinners, high cost of daycare / preschool, whateverver else
3) The increase in signups of both Amex Platinum and Delta Reserve, and people's willingness to pay $500-$800 for a card

Everyone is saying "Delta showed their cards - they want to do XYZ." Well Delta has to devalue, because the current system is probably too easy for many given the current reality