Agreed that this is very click-baity.
1 out of 4 new Delta Amex cards are either Platinum or Reserve high end cards with the latter giving you free access to Delta Sky Clubs when flying Delta.
This doesn't seem that surprising? There are 4 consumer cards (Blue, Gold, Platinum, Reserve), and I have to imagine that in the grand scheme of things, the 3 commercial cards (Biz Gold, Biz Platinum, Biz Reserve) don't have the cards-in-force that the consumer cards do. So, 1/4 of new cards coming from two of the most popular cards almost feels low. Plus, the Delta Platinum has to pay for access at $39 a pop.
If this article had talked about the change in card membership from 2020/2021 to now, then I could see some reason for speculation. This does just seem like click-bait. Or a thinly-veiled way to publish insider information that he recently received.