FWIW I got my first Amex card in decades November 2, 2017 -- BCP for $2000. No prequalified offers at all, I just cold apped because data points I found online said I probably would get approved.
Within 2 weeks of getting BCP, I started seeing "You're pre-approved!" on many credit cards on the Amex site when logged in, but NO "pre-approved" wording on any of the charge cards. In fact, over the past 3 weeks, charge cards started disappearing from the site entirely for me! I can't even SEE that they offer charge cards anymore, except for the Green, and that one still doesn't say "you're pre-approved!" at all, like the credit cards do.
I don't have any need for any more Amex credit cards so I haven't tried anything, but I will check weekly to see if any charge cards that disappeared show back up. I'm definitely gardening to snag the Platinum but I'd consider the PRG.
If you're an Amex customer, log in and check the cards out and see which if any say pre-approved. If none of them do, I'd say your profile doesn't match with what they're looking for, but my Amex login showed pre-approvals at 2 weeks after joining.
My FICO 08 EX is 710, no derogatories whatsoever but a short AoOA (5 years) and very short AAoA (12 months) with AZEO utilization.
